Merge branch 'master' into bump-gecko-media

2025-08-05 21:50:18 +01:00 · 2017-12-18 15:29:20 +01:00 · 2017-12-18 15:29:20 +01:00 · b35c6bc14e
commit b35c6bc14e
parent f7c8a0cb60 3a37d80931
131 changed files with 2480 additions and 1444 deletions
--- a/.taskcluster.yml
+++ b/.taskcluster.yml
@ -0,0 +1,34 @@
 version: 0
 metadata:
  name: servo
  description: >-
    A modern, high-performance browser engine designed for both application
    and embedded use.
  owner: '{{ event.head.user.email }}'
  source: '{{ event.head.repo.url }}'
 tasks:
  - provisionerId: '{{ taskcluster.docker.provisionerId }}'
    workerType: '{{ taskcluster.docker.workerType }}'
    extra:
      github:
        events: []
    payload:
      maxRunTime: 3600
      image: servobrowser/servo-linux-dev
      command:
        - /bin/bash
        - '--login'
        - '-c'
        - '-x'
        - >-
          git clone {{event.head.repo.url}} servo &&
          cd servo &&
          git config advice.detachedHead false &&
          git checkout {{event.head.sha}} &&
          etc/ci/taskcluster-test.sh
    metadata:
      name: linux-tests
      description: Run Linux tests.
      owner: '{{ event.head.user.email }}'
      source: '{{ event.head.repo.url }}'
--- a/Cargo.lock
+++ b/Cargo.lock
@ -47,11 +47,11 @@ source = "registry+https://github.com/rust-lang/crates.io-index"
 [[package]]
 name = "app_units"
-version = "0.6.0"
+version = "0.6.1"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 dependencies = [
 "num-traits 0.1.37 (registry+https://github.com/rust-lang/crates.io-index)",
- "serde 1.0.14 (registry+https://github.com/rust-lang/crates.io-index)",
+ "serde 1.0.23 (git+https://github.com/gankro/serde?branch=deserialize_from_enums3)",
 ]
 [[package]]
@ -143,7 +143,7 @@ version = "0.9.2"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 dependencies = [
 "byteorder 1.2.1 (registry+https://github.com/rust-lang/crates.io-index)",
- "serde 1.0.14 (registry+https://github.com/rust-lang/crates.io-index)",
+ "serde 1.0.23 (git+https://github.com/gankro/serde?branch=deserialize_from_enums3)",
 ]
 [[package]]
@ -204,7 +204,7 @@ version = "0.0.1"
 dependencies = [
 "ipc-channel 0.9.0 (registry+https://github.com/rust-lang/crates.io-index)",
 "regex 0.2.2 (registry+https://github.com/rust-lang/crates.io-index)",
- "serde 1.0.14 (registry+https://github.com/rust-lang/crates.io-index)",
+ "serde 1.0.23 (git+https://github.com/gankro/serde?branch=deserialize_from_enums3)",
 "servo_config 0.0.1",
 ]
@ -287,8 +287,8 @@ dependencies = [
 "num-traits 0.1.37 (registry+https://github.com/rust-lang/crates.io-index)",
 "offscreen_gl_context 0.14.0 (registry+https://github.com/rust-lang/crates.io-index)",
 "servo_config 0.0.1",
- "webrender 0.56.0 (git+https://github.com/servo/webrender)",
+ "webrender 0.56.1 (git+https://github.com/servo/webrender)",
- "webrender_api 0.56.0 (git+https://github.com/servo/webrender)",
+ "webrender_api 0.56.1 (git+https://github.com/servo/webrender)",
 ]
 [[package]]
@ -303,9 +303,9 @@ dependencies = [
 "malloc_size_of_derive 0.0.1",
 "nonzero 0.0.1",
 "offscreen_gl_context 0.14.0 (registry+https://github.com/rust-lang/crates.io-index)",
- "serde 1.0.14 (registry+https://github.com/rust-lang/crates.io-index)",
+ "serde 1.0.23 (git+https://github.com/gankro/serde?branch=deserialize_from_enums3)",
 "servo_config 0.0.1",
- "webrender_api 0.56.0 (git+https://github.com/servo/webrender)",
+ "webrender_api 0.56.1 (git+https://github.com/servo/webrender)",
 ]
 [[package]]
@ -324,7 +324,7 @@ source = "registry+https://github.com/rust-lang/crates.io-index"
 dependencies = [
 "clap 2.28.0 (registry+https://github.com/rust-lang/crates.io-index)",
 "log 0.3.8 (registry+https://github.com/rust-lang/crates.io-index)",
- "serde 1.0.14 (registry+https://github.com/rust-lang/crates.io-index)",
+ "serde 1.0.23 (git+https://github.com/gankro/serde?branch=deserialize_from_enums3)",
 "serde_json 1.0.2 (registry+https://github.com/rust-lang/crates.io-index)",
 "syn 0.11.11 (registry+https://github.com/rust-lang/crates.io-index)",
 "tempdir 0.3.5 (registry+https://github.com/rust-lang/crates.io-index)",
@ -358,6 +358,15 @@ dependencies = [
 "libc 0.2.33 (registry+https://github.com/rust-lang/crates.io-index)",
 ]
 [[package]]
 name = "chrono"
 version = "0.4.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 dependencies = [
 "num 0.1.37 (registry+https://github.com/rust-lang/crates.io-index)",
 "time 0.1.37 (registry+https://github.com/rust-lang/crates.io-index)",
 ]
 [[package]]
 name = "clang-sys"
 version = "0.21.1"
@ -459,8 +468,8 @@ dependencies = [
 "servo_url 0.0.1",
 "style_traits 0.0.1",
 "time 0.1.37 (registry+https://github.com/rust-lang/crates.io-index)",
- "webrender 0.56.0 (git+https://github.com/servo/webrender)",
+ "webrender 0.56.1 (git+https://github.com/servo/webrender)",
- "webrender_api 0.56.0 (git+https://github.com/servo/webrender)",
+ "webrender_api 0.56.1 (git+https://github.com/servo/webrender)",
 ]
 [[package]]
@ -491,13 +500,13 @@ dependencies = [
 "net_traits 0.0.1",
 "profile_traits 0.0.1",
 "script_traits 0.0.1",
- "serde 1.0.14 (registry+https://github.com/rust-lang/crates.io-index)",
+ "serde 1.0.23 (git+https://github.com/gankro/serde?branch=deserialize_from_enums3)",
 "servo_config 0.0.1",
 "servo_rand 0.0.1",
 "servo_remutex 0.0.1",
 "servo_url 0.0.1",
 "style_traits 0.0.1",
- "webrender_api 0.56.0 (git+https://github.com/servo/webrender)",
+ "webrender_api 0.56.1 (git+https://github.com/servo/webrender)",
 "webvr_traits 0.0.1",
 ]
@ -560,7 +569,7 @@ dependencies = [
 "phf 0.7.21 (registry+https://github.com/rust-lang/crates.io-index)",
 "procedural-masquerade 0.1.2 (registry+https://github.com/rust-lang/crates.io-index)",
 "quote 0.3.15 (registry+https://github.com/rust-lang/crates.io-index)",
- "serde 1.0.14 (registry+https://github.com/rust-lang/crates.io-index)",
+ "serde 1.0.23 (git+https://github.com/gankro/serde?branch=deserialize_from_enums3)",
 "smallvec 0.6.0 (registry+https://github.com/rust-lang/crates.io-index)",
 "syn 0.11.11 (registry+https://github.com/rust-lang/crates.io-index)",
 ]
@ -704,7 +713,7 @@ dependencies = [
 "ipc-channel 0.9.0 (registry+https://github.com/rust-lang/crates.io-index)",
 "log 0.3.8 (registry+https://github.com/rust-lang/crates.io-index)",
 "msg 0.0.1",
- "serde 1.0.14 (registry+https://github.com/rust-lang/crates.io-index)",
+ "serde 1.0.23 (git+https://github.com/gankro/serde?branch=deserialize_from_enums3)",
 "serde_json 1.0.2 (registry+https://github.com/rust-lang/crates.io-index)",
 "time 0.1.37 (registry+https://github.com/rust-lang/crates.io-index)",
 ]
@ -720,7 +729,7 @@ dependencies = [
 "malloc_size_of 0.0.1",
 "malloc_size_of_derive 0.0.1",
 "msg 0.0.1",
- "serde 1.0.14 (registry+https://github.com/rust-lang/crates.io-index)",
+ "serde 1.0.23 (git+https://github.com/gankro/serde?branch=deserialize_from_enums3)",
 "servo_url 0.0.1",
 "time 0.1.37 (registry+https://github.com/rust-lang/crates.io-index)",
 ]
@ -768,8 +777,8 @@ dependencies = [
 "kernel32-sys 0.2.2 (registry+https://github.com/rust-lang/crates.io-index)",
 "lazy_static 1.0.0 (registry+https://github.com/rust-lang/crates.io-index)",
 "libc 0.2.33 (registry+https://github.com/rust-lang/crates.io-index)",
- "serde 1.0.14 (registry+https://github.com/rust-lang/crates.io-index)",
+ "serde 1.0.23 (git+https://github.com/gankro/serde?branch=deserialize_from_enums3)",
- "serde_derive 1.0.14 (registry+https://github.com/rust-lang/crates.io-index)",
+ "serde_derive 1.0.23 (git+https://github.com/gankro/serde?branch=deserialize_from_enums3)",
 "winapi 0.2.8 (registry+https://github.com/rust-lang/crates.io-index)",
 ]
@ -799,7 +808,7 @@ dependencies = [
 "servo_geometry 0.0.1",
 "servo_url 0.0.1",
 "style_traits 0.0.1",
- "webrender_api 0.56.0 (git+https://github.com/servo/webrender)",
+ "webrender_api 0.56.1 (git+https://github.com/servo/webrender)",
 "x11 2.14.0 (registry+https://github.com/rust-lang/crates.io-index)",
 ]
@ -893,7 +902,7 @@ source = "registry+https://github.com/rust-lang/crates.io-index"
 dependencies = [
 "log 0.3.8 (registry+https://github.com/rust-lang/crates.io-index)",
 "num-traits 0.1.37 (registry+https://github.com/rust-lang/crates.io-index)",
- "serde 1.0.14 (registry+https://github.com/rust-lang/crates.io-index)",
+ "serde 1.0.23 (git+https://github.com/gankro/serde?branch=deserialize_from_enums3)",
 ]
 [[package]]
@ -1049,7 +1058,7 @@ source = "registry+https://github.com/rust-lang/crates.io-index"
 name = "gfx"
 version = "0.0.1"
 dependencies = [
- "app_units 0.6.0 (registry+https://github.com/rust-lang/crates.io-index)",
+ "app_units 0.6.1 (registry+https://github.com/rust-lang/crates.io-index)",
 "bitflags 1.0.0 (registry+https://github.com/rust-lang/crates.io-index)",
 "byteorder 1.2.1 (registry+https://github.com/rust-lang/crates.io-index)",
 "core-foundation 0.4.6 (registry+https://github.com/rust-lang/crates.io-index)",
@ -1072,7 +1081,7 @@ dependencies = [
 "net_traits 0.0.1",
 "ordered-float 0.4.0 (registry+https://github.com/rust-lang/crates.io-index)",
 "range 0.0.1",
- "serde 1.0.14 (registry+https://github.com/rust-lang/crates.io-index)",
+ "serde 1.0.23 (git+https://github.com/gankro/serde?branch=deserialize_from_enums3)",
 "servo-fontconfig 0.2.1 (registry+https://github.com/rust-lang/crates.io-index)",
 "servo_allocator 0.0.1",
 "servo_arc 0.0.1",
@ -1087,7 +1096,7 @@ dependencies = [
 "truetype 0.26.0 (registry+https://github.com/rust-lang/crates.io-index)",
 "unicode-bidi 0.3.3 (registry+https://github.com/rust-lang/crates.io-index)",
 "unicode-script 0.1.1 (registry+https://github.com/rust-lang/crates.io-index)",
- "webrender_api 0.56.0 (git+https://github.com/servo/webrender)",
+ "webrender_api 0.56.1 (git+https://github.com/servo/webrender)",
 "xi-unicode 0.1.0 (registry+https://github.com/rust-lang/crates.io-index)",
 "xml5ever 0.12.0 (registry+https://github.com/rust-lang/crates.io-index)",
 ]
@ -1109,7 +1118,7 @@ dependencies = [
 "malloc_size_of 0.0.1",
 "malloc_size_of_derive 0.0.1",
 "range 0.0.1",
- "serde 1.0.14 (registry+https://github.com/rust-lang/crates.io-index)",
+ "serde 1.0.23 (git+https://github.com/gankro/serde?branch=deserialize_from_enums3)",
 ]
 [[package]]
@ -1168,7 +1177,7 @@ dependencies = [
 "servo_url 0.0.1",
 "style_traits 0.0.1",
 "user32-sys 0.2.0 (registry+https://github.com/rust-lang/crates.io-index)",
- "webrender_api 0.56.0 (git+https://github.com/servo/webrender)",
+ "webrender_api 0.56.1 (git+https://github.com/servo/webrender)",
 "winapi 0.2.8 (registry+https://github.com/rust-lang/crates.io-index)",
 "x11 2.14.0 (registry+https://github.com/rust-lang/crates.io-index)",
 ]
@ -1283,7 +1292,7 @@ dependencies = [
 "cookie 0.10.1 (registry+https://github.com/rust-lang/crates.io-index)",
 "hyper 0.10.13 (registry+https://github.com/rust-lang/crates.io-index)",
 "mime 0.2.4 (registry+https://github.com/rust-lang/crates.io-index)",
- "serde 1.0.14 (registry+https://github.com/rust-lang/crates.io-index)",
+ "serde 1.0.23 (git+https://github.com/gankro/serde?branch=deserialize_from_enums3)",
 "serde_bytes 0.10.0 (registry+https://github.com/rust-lang/crates.io-index)",
 "time 0.1.37 (registry+https://github.com/rust-lang/crates.io-index)",
 ]
@ -1378,7 +1387,7 @@ dependencies = [
 "libc 0.2.33 (registry+https://github.com/rust-lang/crates.io-index)",
 "mio 0.6.9 (registry+https://github.com/rust-lang/crates.io-index)",
 "rand 0.3.15 (registry+https://github.com/rust-lang/crates.io-index)",
- "serde 1.0.14 (registry+https://github.com/rust-lang/crates.io-index)",
+ "serde 1.0.23 (git+https://github.com/gankro/serde?branch=deserialize_from_enums3)",
 "uuid 0.5.0 (registry+https://github.com/rust-lang/crates.io-index)",
 ]
@ -1454,7 +1463,7 @@ source = "registry+https://github.com/rust-lang/crates.io-index"
 name = "layout"
 version = "0.0.1"
 dependencies = [
- "app_units 0.6.0 (registry+https://github.com/rust-lang/crates.io-index)",
+ "app_units 0.6.1 (registry+https://github.com/rust-lang/crates.io-index)",
 "atomic_refcell 0.1.0 (registry+https://github.com/rust-lang/crates.io-index)",
 "bitflags 1.0.0 (registry+https://github.com/rust-lang/crates.io-index)",
 "canvas_traits 0.0.1",
@ -1477,7 +1486,7 @@ dependencies = [
 "script_layout_interface 0.0.1",
 "script_traits 0.0.1",
 "selectors 0.19.0",
- "serde 1.0.14 (registry+https://github.com/rust-lang/crates.io-index)",
+ "serde 1.0.23 (git+https://github.com/gankro/serde?branch=deserialize_from_enums3)",
 "serde_json 1.0.2 (registry+https://github.com/rust-lang/crates.io-index)",
 "servo_arc 0.0.1",
 "servo_atoms 0.0.1",
@ -1489,7 +1498,7 @@ dependencies = [
 "style_traits 0.0.1",
 "unicode-bidi 0.3.3 (registry+https://github.com/rust-lang/crates.io-index)",
 "unicode-script 0.1.1 (registry+https://github.com/rust-lang/crates.io-index)",
- "webrender_api 0.56.0 (git+https://github.com/servo/webrender)",
+ "webrender_api 0.56.1 (git+https://github.com/servo/webrender)",
 ]
 [[package]]
@ -1504,7 +1513,7 @@ dependencies = [
 name = "layout_thread"
 version = "0.0.1"
 dependencies = [
- "app_units 0.6.0 (registry+https://github.com/rust-lang/crates.io-index)",
+ "app_units 0.6.1 (registry+https://github.com/rust-lang/crates.io-index)",
 "atomic_refcell 0.1.0 (registry+https://github.com/rust-lang/crates.io-index)",
 "euclid 0.16.0 (registry+https://github.com/rust-lang/crates.io-index)",
 "fnv 1.0.5 (registry+https://github.com/rust-lang/crates.io-index)",
@ -1539,7 +1548,7 @@ dependencies = [
 "servo_url 0.0.1",
 "style 0.0.1",
 "style_traits 0.0.1",
- "webrender_api 0.56.0 (git+https://github.com/servo/webrender)",
+ "webrender_api 0.56.1 (git+https://github.com/servo/webrender)",
 ]
 [[package]]
@ -1554,7 +1563,7 @@ dependencies = [
 "profile_traits 0.0.1",
 "script_traits 0.0.1",
 "servo_url 0.0.1",
- "webrender_api 0.56.0 (git+https://github.com/servo/webrender)",
+ "webrender_api 0.56.1 (git+https://github.com/servo/webrender)",
 ]
 [[package]]
@ -1635,8 +1644,8 @@ dependencies = [
 "style 0.0.1",
 "style_traits 0.0.1",
 "webdriver_server 0.0.1",
- "webrender 0.56.0 (git+https://github.com/servo/webrender)",
+ "webrender 0.56.1 (git+https://github.com/servo/webrender)",
- "webrender_api 0.56.0 (git+https://github.com/servo/webrender)",
+ "webrender_api 0.56.1 (git+https://github.com/servo/webrender)",
 "webvr 0.0.1",
 "webvr_traits 0.0.1",
 ]
@ -1679,7 +1688,7 @@ dependencies = [
 name = "malloc_size_of"
 version = "0.0.1"
 dependencies = [
- "app_units 0.6.0 (registry+https://github.com/rust-lang/crates.io-index)",
+ "app_units 0.6.1 (registry+https://github.com/rust-lang/crates.io-index)",
 "cssparser 0.23.2 (registry+https://github.com/rust-lang/crates.io-index)",
 "euclid 0.16.0 (registry+https://github.com/rust-lang/crates.io-index)",
 "hashglobe 0.1.0",
@ -1689,7 +1698,7 @@ dependencies = [
 "smallvec 0.6.0 (registry+https://github.com/rust-lang/crates.io-index)",
 "string_cache 0.7.1 (registry+https://github.com/rust-lang/crates.io-index)",
 "url 1.6.0 (registry+https://github.com/rust-lang/crates.io-index)",
- "webrender_api 0.56.0 (git+https://github.com/servo/webrender)",
+ "webrender_api 0.56.1 (git+https://github.com/servo/webrender)",
 "xml5ever 0.12.0 (registry+https://github.com/rust-lang/crates.io-index)",
 ]
@ -1717,8 +1726,8 @@ source = "registry+https://github.com/rust-lang/crates.io-index"
 dependencies = [
 "phf 0.7.21 (registry+https://github.com/rust-lang/crates.io-index)",
 "phf_codegen 0.7.21 (registry+https://github.com/rust-lang/crates.io-index)",
- "serde 1.0.14 (registry+https://github.com/rust-lang/crates.io-index)",
+ "serde 1.0.23 (git+https://github.com/gankro/serde?branch=deserialize_from_enums3)",
- "serde_derive 1.0.14 (registry+https://github.com/rust-lang/crates.io-index)",
+ "serde_derive 1.0.23 (git+https://github.com/gankro/serde?branch=deserialize_from_enums3)",
 "serde_json 1.0.2 (registry+https://github.com/rust-lang/crates.io-index)",
 "string_cache 0.7.1 (registry+https://github.com/rust-lang/crates.io-index)",
 "string_cache_codegen 0.4.0 (registry+https://github.com/rust-lang/crates.io-index)",
@ -1907,8 +1916,8 @@ dependencies = [
 "malloc_size_of 0.0.1",
 "malloc_size_of_derive 0.0.1",
 "nonzero 0.0.1",
- "serde 1.0.14 (registry+https://github.com/rust-lang/crates.io-index)",
+ "serde 1.0.23 (git+https://github.com/gankro/serde?branch=deserialize_from_enums3)",
- "webrender_api 0.56.0 (git+https://github.com/servo/webrender)",
+ "webrender_api 0.56.1 (git+https://github.com/servo/webrender)",
 ]
 [[package]]
@ -1942,7 +1951,7 @@ dependencies = [
 "net_traits 0.0.1",
 "openssl 0.9.22 (registry+https://github.com/rust-lang/crates.io-index)",
 "profile_traits 0.0.1",
- "serde 1.0.14 (registry+https://github.com/rust-lang/crates.io-index)",
+ "serde 1.0.23 (git+https://github.com/gankro/serde?branch=deserialize_from_enums3)",
 "serde_json 1.0.2 (registry+https://github.com/rust-lang/crates.io-index)",
 "servo-websocket 0.20.0 (registry+https://github.com/rust-lang/crates.io-index)",
 "servo_config 0.0.1",
@ -1953,7 +1962,7 @@ dependencies = [
 "unicase 1.4.0 (registry+https://github.com/rust-lang/crates.io-index)",
 "url 1.6.0 (registry+https://github.com/rust-lang/crates.io-index)",
 "uuid 0.5.0 (registry+https://github.com/rust-lang/crates.io-index)",
- "webrender_api 0.56.0 (git+https://github.com/servo/webrender)",
+ "webrender_api 0.56.1 (git+https://github.com/servo/webrender)",
 ]
 [[package]]
@ -2005,12 +2014,12 @@ dependencies = [
 "malloc_size_of_derive 0.0.1",
 "msg 0.0.1",
 "num-traits 0.1.37 (registry+https://github.com/rust-lang/crates.io-index)",
- "serde 1.0.14 (registry+https://github.com/rust-lang/crates.io-index)",
+ "serde 1.0.23 (git+https://github.com/gankro/serde?branch=deserialize_from_enums3)",
 "servo_config 0.0.1",
 "servo_url 0.0.1",
 "url 1.6.0 (registry+https://github.com/rust-lang/crates.io-index)",
 "uuid 0.5.0 (registry+https://github.com/rust-lang/crates.io-index)",
- "webrender_api 0.56.0 (git+https://github.com/servo/webrender)",
+ "webrender_api 0.56.1 (git+https://github.com/servo/webrender)",
 ]
 [[package]]
@ -2034,7 +2043,7 @@ source = "registry+https://github.com/rust-lang/crates.io-index"
 name = "nonzero"
 version = "0.0.1"
 dependencies = [
- "serde 1.0.14 (registry+https://github.com/rust-lang/crates.io-index)",
+ "serde 1.0.23 (git+https://github.com/gankro/serde?branch=deserialize_from_enums3)",
 ]
 [[package]]
@ -2044,6 +2053,16 @@ dependencies = [
 "bitflags 1.0.0 (registry+https://github.com/rust-lang/crates.io-index)",
 ]
 [[package]]
 name = "num"
 version = "0.1.37"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 dependencies = [
 "num-integer 0.1.34 (registry+https://github.com/rust-lang/crates.io-index)",
 "num-iter 0.1.33 (registry+https://github.com/rust-lang/crates.io-index)",
 "num-traits 0.1.37 (registry+https://github.com/rust-lang/crates.io-index)",
 ]
 [[package]]
 name = "num-integer"
 version = "0.1.34"
@ -2126,7 +2145,7 @@ dependencies = [
 "log 0.3.8 (registry+https://github.com/rust-lang/crates.io-index)",
 "objc 0.2.2 (registry+https://github.com/rust-lang/crates.io-index)",
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- "serde 1.0.14 (registry+https://github.com/rust-lang/crates.io-index)",
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- "serde 1.0.14 (registry+https://github.com/rust-lang/crates.io-index)",
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- "serde 1.0.14 (registry+https://github.com/rust-lang/crates.io-index)",
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 "num-traits 0.1.37 (registry+https://github.com/rust-lang/crates.io-index)",
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+ "serde 1.0.23 (git+https://github.com/gankro/serde?branch=deserialize_from_enums3)",
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 [[package]]
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- "serde 1.0.14 (registry+https://github.com/rust-lang/crates.io-index)",
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- "serde_derive 1.0.14 (registry+https://github.com/rust-lang/crates.io-index)",
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@ -2530,7 +2549,7 @@ name = "script"
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- "app_units 0.6.0 (registry+https://github.com/rust-lang/crates.io-index)",
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@ -2538,6 +2557,7 @@ dependencies = [
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@ -2585,7 +2605,7 @@ dependencies = [
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 "script_traits 0.0.1",
 "selectors 0.19.0",
- "serde 1.0.14 (registry+https://github.com/rust-lang/crates.io-index)",
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- "webrender_api 0.56.0 (git+https://github.com/servo/webrender)",
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 "webvr_traits 0.0.1",
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@ -2613,7 +2633,7 @@ dependencies = [
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 version = "0.0.1"
 dependencies = [
- "app_units 0.6.0 (registry+https://github.com/rust-lang/crates.io-index)",
+ "app_units 0.6.1 (registry+https://github.com/rust-lang/crates.io-index)",
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 "canvas_traits 0.0.1",
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@ -2637,7 +2657,7 @@ dependencies = [
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 "servo_url 0.0.1",
 "style 0.0.1",
- "webrender_api 0.56.0 (git+https://github.com/servo/webrender)",
+ "webrender_api 0.56.1 (git+https://github.com/servo/webrender)",
 ]
 [[package]]
@ -2682,13 +2702,13 @@ dependencies = [
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 "rustc-serialize 0.3.24 (registry+https://github.com/rust-lang/crates.io-index)",
- "serde 1.0.14 (registry+https://github.com/rust-lang/crates.io-index)",
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- "webrender_api 0.56.0 (git+https://github.com/servo/webrender)",
+ "webrender_api 0.56.1 (git+https://github.com/servo/webrender)",
 "webvr_traits 0.0.1",
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@ -2731,10 +2751,10 @@ source = "registry+https://github.com/rust-lang/crates.io-index"
 [[package]]
 name = "serde"
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-source = "registry+https://github.com/rust-lang/crates.io-index"
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 dependencies = [
- "serde_derive 1.0.14 (registry+https://github.com/rust-lang/crates.io-index)",
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 [[package]]
@ -2742,23 +2762,23 @@ name = "serde_bytes"
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 source = "registry+https://github.com/rust-lang/crates.io-index"
 dependencies = [
- "serde 1.0.14 (registry+https://github.com/rust-lang/crates.io-index)",
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 ]
 [[package]]
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- "serde_derive_internals 0.16.0 (registry+https://github.com/rust-lang/crates.io-index)",
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 "syn 0.11.11 (registry+https://github.com/rust-lang/crates.io-index)",
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 [[package]]
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-source = "registry+https://github.com/rust-lang/crates.io-index"
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@ -2772,7 +2792,7 @@ dependencies = [
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- "serde 1.0.14 (registry+https://github.com/rust-lang/crates.io-index)",
+ "serde 1.0.23 (git+https://github.com/gankro/serde?branch=deserialize_from_enums3)",
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 [[package]]
@ -2900,7 +2920,7 @@ name = "servo_arc"
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 "nodrop 0.1.12 (registry+https://github.com/rust-lang/crates.io-index)",
- "serde 1.0.14 (registry+https://github.com/rust-lang/crates.io-index)",
+ "serde 1.0.23 (git+https://github.com/gankro/serde?branch=deserialize_from_enums3)",
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@ -2924,7 +2944,7 @@ dependencies = [
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- "serde 1.0.14 (registry+https://github.com/rust-lang/crates.io-index)",
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 "servo_url 0.0.1",
 "url 1.6.0 (registry+https://github.com/rust-lang/crates.io-index)",
@ -2942,7 +2962,7 @@ dependencies = [
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 version = "0.0.1"
 dependencies = [
- "app_units 0.6.0 (registry+https://github.com/rust-lang/crates.io-index)",
+ "app_units 0.6.1 (registry+https://github.com/rust-lang/crates.io-index)",
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 "malloc_size_of 0.0.1",
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 "malloc_size_of_derive 0.0.1",
- "serde 1.0.14 (registry+https://github.com/rust-lang/crates.io-index)",
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- "serde 1.0.14 (registry+https://github.com/rust-lang/crates.io-index)",
+ "serde 1.0.23 (git+https://github.com/gankro/serde?branch=deserialize_from_enums3)",
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@ -3092,7 +3112,7 @@ source = "registry+https://github.com/rust-lang/crates.io-index"
 name = "style"
 version = "0.0.1"
 dependencies = [
- "app_units 0.6.0 (registry+https://github.com/rust-lang/crates.io-index)",
+ "app_units 0.6.1 (registry+https://github.com/rust-lang/crates.io-index)",
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@ -3125,7 +3145,7 @@ dependencies = [
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 "selectors 0.19.0",
- "serde 1.0.14 (registry+https://github.com/rust-lang/crates.io-index)",
+ "serde 1.0.23 (git+https://github.com/gankro/serde?branch=deserialize_from_enums3)",
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 "servo_atoms 0.0.1",
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@ -3156,7 +3176,7 @@ dependencies = [
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 version = "0.0.1"
 dependencies = [
- "app_units 0.6.0 (registry+https://github.com/rust-lang/crates.io-index)",
+ "app_units 0.6.1 (registry+https://github.com/rust-lang/crates.io-index)",
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@ -3178,17 +3198,17 @@ dependencies = [
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 version = "0.0.1"
 dependencies = [
- "app_units 0.6.0 (registry+https://github.com/rust-lang/crates.io-index)",
+ "app_units 0.6.1 (registry+https://github.com/rust-lang/crates.io-index)",
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- "serde 1.0.14 (registry+https://github.com/rust-lang/crates.io-index)",
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 "servo_atoms 0.0.1",
- "webrender_api 0.56.0 (git+https://github.com/servo/webrender)",
+ "webrender_api 0.56.1 (git+https://github.com/servo/webrender)",
 ]
 [[package]]
@ -3344,7 +3364,7 @@ name = "toml"
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 source = "registry+https://github.com/rust-lang/crates.io-index"
 dependencies = [
- "serde 1.0.14 (registry+https://github.com/rust-lang/crates.io-index)",
+ "serde 1.0.23 (git+https://github.com/gankro/serde?branch=deserialize_from_enums3)",
 ]
 [[package]]
@ -3392,8 +3412,8 @@ version = "0.3.3"
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- "serde 1.0.14 (registry+https://github.com/rust-lang/crates.io-index)",
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- "serde_derive 1.0.14 (registry+https://github.com/rust-lang/crates.io-index)",
+ "serde_derive 1.0.23 (git+https://github.com/gankro/serde?branch=deserialize_from_enums3)",
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 [[package]]
@ -3447,7 +3467,7 @@ name = "url_serde"
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 source = "registry+https://github.com/rust-lang/crates.io-index"
 dependencies = [
- "serde 1.0.14 (registry+https://github.com/rust-lang/crates.io-index)",
+ "serde 1.0.23 (git+https://github.com/gankro/serde?branch=deserialize_from_enums3)",
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@ -3479,7 +3499,7 @@ version = "0.5.0"
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- "serde 1.0.14 (registry+https://github.com/rust-lang/crates.io-index)",
+ "serde 1.0.23 (git+https://github.com/gankro/serde?branch=deserialize_from_enums3)",
 ]
 [[package]]
@ -3546,10 +3566,10 @@ dependencies = [
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-source = "git+https://github.com/servo/webrender#0e80c9d04f84fd02de94bb61c5a5b4b5d16d94b5"
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 dependencies = [
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- "webrender_api 0.56.0 (git+https://github.com/servo/webrender)",
+ "webrender_api 0.56.1 (git+https://github.com/servo/webrender)",
 ]
 [[package]]
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-source = "git+https://github.com/servo/webrender#0e80c9d04f84fd02de94bb61c5a5b4b5d16d94b5"
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 dependencies = [
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- "serde 1.0.14 (registry+https://github.com/rust-lang/crates.io-index)",
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@ -3612,7 +3633,7 @@ dependencies = [
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- "serde 1.0.14 (registry+https://github.com/rust-lang/crates.io-index)",
+ "serde 1.0.23 (git+https://github.com/gankro/serde?branch=deserialize_from_enums3)",
 ]
 [[package]]
@ -3732,7 +3753,7 @@ dependencies = [
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-"checksum app_units 0.6.0 (registry+https://github.com/rust-lang/crates.io-index)" = "29069a9b483f7780aebb55dafb360c6225eefdc1f98c8d336a65148fd10c37b1"
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 "checksum atomic_refcell 0.1.0 (registry+https://github.com/rust-lang/crates.io-index)" = "fb2dcb6e6d35f20276943cc04bb98e538b348d525a04ac79c10021561d202f21"
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@ -3763,6 +3784,7 @@ dependencies = [
 "checksum cexpr 0.2.0 (registry+https://github.com/rust-lang/crates.io-index)" = "393a5f0088efbe41f9d1fcd062f24e83c278608420e62109feb2c8abee07de7d"
 "checksum cfg-if 0.1.2 (registry+https://github.com/rust-lang/crates.io-index)" = "d4c819a1287eb618df47cc647173c5c4c66ba19d888a6e50d605672aed3140de"
 "checksum cgl 0.2.1 (registry+https://github.com/rust-lang/crates.io-index)" = "86765cb42c2a2c497e142af72517c1b4d7ae5bb2f25dfa77a5c69642f2342d89"
 "checksum chrono 0.4.0 (registry+https://github.com/rust-lang/crates.io-index)" = "7c20ebe0b2b08b0aeddba49c609fe7957ba2e33449882cb186a180bc60682fa9"
 "checksum clang-sys 0.21.1 (registry+https://github.com/rust-lang/crates.io-index)" = "00048189ee171715296dfe3b2fcfd439563c7bfec0d98d3976ce3402d62c8f07"
 "checksum clap 2.28.0 (registry+https://github.com/rust-lang/crates.io-index)" = "dc34bf7d5d66268b466b9852bca925ec1d2650654dab4da081e63fd230145c2e"
 "checksum clipboard 0.4.0 (registry+https://github.com/rust-lang/crates.io-index)" = "dd3a9a938558f33ec1baaa6ca631a69c104aafaacbc66868d9ad28cf5f30564f"
@ -3882,6 +3904,7 @@ dependencies = [
 "checksum net2 0.2.29 (registry+https://github.com/rust-lang/crates.io-index)" = "bc01404e7568680f1259aa5729539f221cb1e6d047a0d9053cab4be8a73b5d67"
 "checksum nodrop 0.1.12 (registry+https://github.com/rust-lang/crates.io-index)" = "9a2228dca57108069a5262f2ed8bd2e82496d2e074a06d1ccc7ce1687b6ae0a2"
 "checksum nom 1.2.4 (registry+https://github.com/rust-lang/crates.io-index)" = "a5b8c256fd9471521bcb84c3cdba98921497f1a331cbc15b8030fc63b82050ce"
 "checksum num 0.1.37 (registry+https://github.com/rust-lang/crates.io-index)" = "98b15ba84e910ea7a1973bccd3df7b31ae282bf9d8bd2897779950c9b8303d40"
 "checksum num-integer 0.1.34 (registry+https://github.com/rust-lang/crates.io-index)" = "ef1a4bf6f9174aa5783a9b4cc892cacd11aebad6c69ad027a0b65c6ca5f8aa37"
 "checksum num-iter 0.1.33 (registry+https://github.com/rust-lang/crates.io-index)" = "f7d1891bd7b936f12349b7d1403761c8a0b85a18b148e9da4429d5d102c1a41e"
 "checksum num-rational 0.1.36 (registry+https://github.com/rust-lang/crates.io-index)" = "c2dc5ea04020a8f18318ae485c751f8cfa1c0e69dcf465c29ddaaa64a313cc44"
@ -3938,10 +3961,10 @@ dependencies = [
 "checksum semver 0.1.20 (registry+https://github.com/rust-lang/crates.io-index)" = "d4f410fedcf71af0345d7607d246e7ad15faaadd49d240ee3b24e5dc21a820ac"
 "checksum semver 0.6.0 (registry+https://github.com/rust-lang/crates.io-index)" = "7a3186ec9e65071a2095434b1f5bb24838d4e8e130f584c790f6033c79943537"
 "checksum semver-parser 0.7.0 (registry+https://github.com/rust-lang/crates.io-index)" = "388a1df253eca08550bef6c72392cfe7c30914bf41df5269b68cbd6ff8f570a3"
-"checksum serde 1.0.14 (registry+https://github.com/rust-lang/crates.io-index)" = "bcb6a7637a47663ee073391a139ed07851f27ed2532c2abc88c6bf27a16cdf34"
+"checksum serde 1.0.23 (git+https://github.com/gankro/serde?branch=deserialize_from_enums3)" = "<none>"
 "checksum serde_bytes 0.10.0 (registry+https://github.com/rust-lang/crates.io-index)" = "7a73f5ad9bb83e1e407254c7a355f4efdaffe3c1442fc0657ddb8b9b6b225655"
-"checksum serde_derive 1.0.14 (registry+https://github.com/rust-lang/crates.io-index)" = "812ff66056fd9a9a5b7c119714243b0862cf98340e7d4b5ee05a932c40d5ea6c"
+"checksum serde_derive 1.0.23 (git+https://github.com/gankro/serde?branch=deserialize_from_enums3)" = "<none>"
-"checksum serde_derive_internals 0.16.0 (registry+https://github.com/rust-lang/crates.io-index)" = "bd381f6d01a6616cdba8530492d453b7761b456ba974e98768a18cad2cd76f58"
+"checksum serde_derive_internals 0.17.0 (git+https://github.com/gankro/serde?branch=deserialize_from_enums3)" = "<none>"
 "checksum serde_json 1.0.2 (registry+https://github.com/rust-lang/crates.io-index)" = "48b04779552e92037212c3615370f6bd57a40ebba7f20e554ff9f55e41a69a7b"
 "checksum servo-egl 0.2.1 (registry+https://github.com/rust-lang/crates.io-index)" = "21069a884c33fe6ee596975e1f3849ed88c4ec857fbaf11d33672d8ebe051217"
 "checksum servo-fontconfig 0.2.1 (registry+https://github.com/rust-lang/crates.io-index)" = "93f799b649b4a2bf362398910eca35240704c7e765e780349b2bb1070d892262"
@ -4005,8 +4028,8 @@ dependencies = [
 "checksum void 1.0.2 (registry+https://github.com/rust-lang/crates.io-index)" = "6a02e4885ed3bc0f2de90ea6dd45ebcbb66dacffe03547fadbb0eeae2770887d"
 "checksum walkdir 1.0.7 (registry+https://github.com/rust-lang/crates.io-index)" = "bb08f9e670fab86099470b97cd2b252d6527f0b3cc1401acdb595ffc9dd288ff"
 "checksum webdriver 0.33.0 (registry+https://github.com/rust-lang/crates.io-index)" = "6577005cf83a9df4ba39910f8baf3b835b5e4a0a5e9a0d71f3eceae6214ebf28"
-"checksum webrender 0.56.0 (git+https://github.com/servo/webrender)" = "<none>"
+"checksum webrender 0.56.1 (git+https://github.com/servo/webrender)" = "<none>"
-"checksum webrender_api 0.56.0 (git+https://github.com/servo/webrender)" = "<none>"
+"checksum webrender_api 0.56.1 (git+https://github.com/servo/webrender)" = "<none>"
 "checksum which 1.0.3 (registry+https://github.com/rust-lang/crates.io-index)" = "4be6cfa54dab45266e98b5d7be2f8ce959ddd49abd141a05d52dce4b07f803bb"
 "checksum winapi 0.2.8 (registry+https://github.com/rust-lang/crates.io-index)" = "167dc9d6949a9b857f3451275e911c3f44255842c1f7a76f33c55103a909087a"
 "checksum winapi-build 0.1.1 (registry+https://github.com/rust-lang/crates.io-index)" = "2d315eee3b34aca4797b2da6b13ed88266e6d612562a0c46390af8299fc699bc"
--- a/Cargo.toml
+++ b/Cargo.toml
@ -24,6 +24,9 @@ opt-level = 3
 # lto = false
 [patch.crates-io]
 serde = { git = "https://github.com/gankro/serde", branch = "deserialize_from_enums3" }
 serde_derive = { git = "https://github.com/gankro/serde", branch = "deserialize_from_enums3", feature="deserialize_from" }
 # If you need to temporarily test Servo with a local fork of some upstream
 # crate, add that here. Use the form:
 #
--- a/README.md
+++ b/README.md
@ -4,7 +4,7 @@
 Servo is a prototype web browser engine written in the
 [Rust](https://github.com/rust-lang/rust) language. It is currently developed on
-64-bit OS X, 64-bit Linux, and Android.
+64-bit OS X, 64-bit Linux, 64-bit Windows, and Android.
 Servo welcomes contribution from everyone.  See
 [`CONTRIBUTING.md`](CONTRIBUTING.md) and [`HACKING_QUICKSTART.md`](docs/HACKING_QUICKSTART.md)
--- a/components/canvas/canvas_paint_thread.rs
+++ b/components/canvas/canvas_paint_thread.rs
@ -11,7 +11,7 @@ use azure::azure_hl::SurfacePattern;
 use canvas_traits::canvas::*;
 use cssparser::RGBA;
 use euclid::{Transform2D, Point2D, Vector2D, Rect, Size2D};
-use ipc_channel::ipc::{self, IpcSender};
+use ipc_channel::ipc::{IpcSender, IpcReceiver};
 use num_traits::ToPrimitive;
 use std::borrow::ToOwned;
 use std::mem;
@ -118,9 +118,8 @@ impl<'a> CanvasPaintThread<'a> {
    /// communicate with it.
    pub fn start(size: Size2D<i32>,
                 webrender_api_sender: webrender_api::RenderApiSender,
-                 antialias: bool)
+                 antialias: bool,
-                 -> IpcSender<CanvasMsg> {
+                 receiver: IpcReceiver<CanvasMsg>) {
        let (sender, receiver) = ipc::channel::<CanvasMsg>().unwrap();
        let antialias = if antialias {
            AntialiasMode::Default
        } else {
@ -216,8 +215,6 @@ impl<'a> CanvasPaintThread<'a> {
                }
            }
        }).expect("Thread spawning failed");
        sender
    }
    fn save_context_state(&mut self) {
--- a/components/constellation/browsingcontext.rs
+++ b/components/constellation/browsingcontext.rs
@ -167,10 +167,7 @@ impl<'a> Iterator for FullyActiveBrowsingContextsIterator<'a> {
    type Item = &'a BrowsingContext;
    fn next(&mut self) -> Option<&'a BrowsingContext> {
        loop {
-            let browsing_context_id = match self.stack.pop() {
+            let browsing_context_id = self.stack.pop()?;
                Some(browsing_context_id) => browsing_context_id,
                None => return None,
            };
            let browsing_context = match self.browsing_contexts.get(&browsing_context_id) {
                Some(browsing_context) => browsing_context,
                None => {
@ -212,10 +209,7 @@ impl<'a> Iterator for AllBrowsingContextsIterator<'a> {
    fn next(&mut self) -> Option<&'a BrowsingContext> {
        let pipelines = self.pipelines;
        loop {
-            let browsing_context_id = match self.stack.pop() {
+            let browsing_context_id = self.stack.pop()?;
                Some(browsing_context_id) => browsing_context_id,
                None => return None,
            };
            let browsing_context = match self.browsing_contexts.get(&browsing_context_id) {
                Some(browsing_context) => browsing_context,
                None => {
--- a/components/constellation/constellation.rs
+++ b/components/constellation/constellation.rs
@ -1235,9 +1235,9 @@ impl<Message, LTF, STF> Constellation<Message, LTF, STF>
                    self.embedder_proxy.send(EmbedderMsg::HeadParsed(source_top_ctx_id));
                }
            }
-            FromScriptMsg::CreateCanvasPaintThread(size, sender) => {
+            FromScriptMsg::CreateCanvasPaintThread(size, receiver) => {
                debug!("constellation got create-canvas-paint-thread message");
-                self.handle_create_canvas_paint_thread_msg(&size, sender)
+                self.handle_create_canvas_paint_thread_msg(&size, receiver)
            }
            FromScriptMsg::NodeStatus(message) => {
                debug!("constellation got NodeStatus message");
@ -2264,13 +2264,12 @@ impl<Message, LTF, STF> Constellation<Message, LTF, STF>
    fn handle_create_canvas_paint_thread_msg(
            &mut self,
            size: &Size2D<i32>,
-            response_sender: IpcSender<IpcSender<CanvasMsg>>) {
+            receiver: IpcReceiver<CanvasMsg>) {
        let webrender_api = self.webrender_api_sender.clone();
-        let sender = CanvasPaintThread::start(*size, webrender_api,
+        CanvasPaintThread::start(*size,
-                                              opts::get().enable_canvas_antialiasing);
+                                 webrender_api,
-        if let Err(e) = response_sender.send(sender) {
+                                 opts::get().enable_canvas_antialiasing,
-            warn!("Create canvas paint thread response failed ({})", e);
+                                 receiver);
        }
    }
    fn handle_webdriver_msg(&mut self, msg: WebDriverCommandMsg) {
--- a/components/gfx/display_list/mod.rs
+++ b/components/gfx/display_list/mod.rs
@ -720,6 +720,15 @@ pub struct GradientDisplayItem {
    /// Contains all gradient data. Included start, end point and color stops.
    pub gradient: Gradient,
    /// The size of a single gradient tile.
    ///
    /// The gradient may fill an entire element background
    /// but it can be composed from many smaller copys of
    /// the same gradient.
    ///
    /// Without tiles, the tile will be the same size as the background.
    pub tile: Size2D<Au>,
 }
 /// Paints a radial gradient.
@ -745,6 +754,15 @@ pub struct RadialGradientDisplayItem {
    /// Contains all gradient data.
    pub gradient: RadialGradient,
    /// The size of a single gradient tile.
    ///
    /// The gradient may fill an entire element background
    /// but it can be composed from many smaller copys of
    /// the same gradient.
    ///
    /// Without tiles, the tile will be the same size as the background.
    pub tile: Size2D<Au>,
 }
 /// A normal border, supporting CSS border styles.
--- a/components/gfx/platform/macos/font.rs
+++ b/components/gfx/platform/macos/font.rs
@ -69,11 +69,7 @@ impl FontHandle {
    /// Cache all the data needed for basic horizontal kerning. This is used only as a fallback or
    /// fast path (when the GPOS table is missing or unnecessary) so it needn't handle every case.
    fn find_h_kern_subtable(&self) -> Option<CachedKernTable> {
-        let font_table = match self.table_for_tag(KERN) {
+        let font_table = self.table_for_tag(KERN)?;
            Some(table) => table,
            None => return None
        };
        let mut result = CachedKernTable {
            font_table: font_table,
            pair_data_range: 0..0,
--- a/components/gfx/text/text_run.rs
+++ b/components/gfx/text/text_run.rs
@ -149,10 +149,7 @@ impl<'a> Iterator for CharacterSliceIterator<'a> {
    // inline(always) due to the inefficient rt failures messing up inline heuristics, I think.
    #[inline(always)]
    fn next(&mut self) -> Option<TextRunSlice<'a>> {
-        let glyph_run = match self.glyph_run {
+        let glyph_run = self.glyph_run?;
            None => return None,
            Some(glyph_run) => glyph_run,
        };
        debug_assert!(!self.range.is_empty());
        let byte_start = self.range.begin();
--- a/components/hashglobe/src/hash_set.rs
+++ b/components/hashglobe/src/hash_set.rs
@ -1051,13 +1051,9 @@ impl<'a, T, S> Iterator for Intersection<'a, T, S>
    fn next(&mut self) -> Option<&'a T> {
        loop {
-            match self.iter.next() {
+            let elt = self.iter.next()?;
-                None => return None,
+            if self.other.contains(elt) {
-                Some(elt) => {
+                return Some(elt);
                    if self.other.contains(elt) {
                        return Some(elt);
                    }
                }
            }
        }
    }
@ -1091,13 +1087,9 @@ impl<'a, T, S> Iterator for Difference<'a, T, S>
    fn next(&mut self) -> Option<&'a T> {
        loop {
-            match self.iter.next() {
+            let elt = self.iter.next()?;
-                None => return None,
+            if !self.other.contains(elt) {
-                Some(elt) => {
+                return Some(elt);
                    if !self.other.contains(elt) {
                        return Some(elt);
                    }
                }
            }
        }
    }
--- a/components/layout/Cargo.toml
+++ b/components/layout/Cargo.toml
@ -10,7 +10,7 @@ name = "layout"
 path = "lib.rs"
 [dependencies]
-app_units = "0.6"
+app_units = "0.6.1"
 atomic_refcell = "0.1"
 bitflags = "1.0"
 canvas_traits = {path = "../canvas_traits"}
@ -41,7 +41,7 @@ serde_json = "1.0"
 servo_config = {path = "../config"}
 servo_url = {path = "../url"}
 smallvec = "0.6"
-style = {path = "../style"}
+style = {path = "../style", features = ["servo"]}
 style_traits = {path = "../style_traits"}
 unicode-bidi = {version = "0.3", features = ["with_serde"]}
 unicode-script = {version = "0.1", features = ["harfbuzz"]}
--- a/components/layout/animation.rs
+++ b/components/layout/animation.rs
@ -5,7 +5,7 @@
 //! CSS transitions and animations.
 use context::LayoutContext;
-use flow::{self, Flow};
+use flow::{Flow, GetBaseFlow};
 use fnv::FnvHashMap;
 use gfx::display_list::OpaqueNode;
 use ipc_channel::ipc::IpcSender;
@ -170,7 +170,7 @@ pub fn recalc_style_for_animations(context: &LayoutContext,
        }
    });
-    let base = flow::mut_base(flow);
+    let base = flow.mut_base();
    base.restyle_damage.insert(damage);
    for kid in base.children.iter_mut() {
        recalc_style_for_animations(context, kid, animations)
--- a/components/layout/block.rs
+++ b/components/layout/block.rs
@ -34,7 +34,7 @@ use display_list_builder::{DisplayListBuildState, StackingContextCollectionFlags
 use display_list_builder::StackingContextCollectionState;
 use euclid::{Point2D, Rect, SideOffsets2D, Size2D};
 use floats::{ClearType, FloatKind, Floats, PlacementInfo};
-use flow::{self, BaseFlow, EarlyAbsolutePositionInfo, Flow, FlowClass, ForceNonfloatedFlag};
+use flow::{BaseFlow, EarlyAbsolutePositionInfo, Flow, FlowClass, ForceNonfloatedFlag, GetBaseFlow};
 use flow::{ImmutableFlowUtils, LateAbsolutePositionInfo, OpaqueFlow, FragmentationContext, FlowFlags};
 use flow_list::FlowList;
 use fragment::{CoordinateSystem, Fragment, FragmentBorderBoxIterator, Overflow, FragmentFlags};
@ -708,7 +708,7 @@ impl BlockFlow {
        // Shift all kids down (or up, if margins are negative) if necessary.
        if block_start_margin_value != Au(0) {
            for kid in self.base.child_iter_mut() {
-                let kid_base = flow::mut_base(kid);
+                let kid_base = kid.mut_base();
                kid_base.position.start.b = kid_base.position.start.b + block_start_margin_value
            }
        }
@ -744,7 +744,7 @@ impl BlockFlow {
    /// is also needed to handle RTL.)
    fn propagate_early_absolute_position_info_to_children(&mut self) {
        for kid in self.base.child_iter_mut() {
-            flow::mut_base(kid).early_absolute_position_info = EarlyAbsolutePositionInfo {
+            kid.mut_base().early_absolute_position_info = EarlyAbsolutePositionInfo {
                relative_containing_block_size: self.fragment.content_box().size,
                relative_containing_block_mode: self.fragment.style().writing_mode,
            }
@ -816,19 +816,19 @@ impl BlockFlow {
            let thread_id = self.base.thread_id;
            let (mut had_floated_children, mut had_children_with_clearance) = (false, false);
            for (child_index, kid) in self.base.child_iter_mut().enumerate() {
-                if flow::base(kid).flags.contains(FlowFlags::IS_ABSOLUTELY_POSITIONED) {
+                if kid.base().flags.contains(FlowFlags::IS_ABSOLUTELY_POSITIONED) {
                    // Assume that the *hypothetical box* for an absolute flow starts immediately
                    // after the margin-end border edge of the previous flow.
-                    if flow::base(kid).flags.contains(FlowFlags::BLOCK_POSITION_IS_STATIC) {
+                    if kid.base().flags.contains(FlowFlags::BLOCK_POSITION_IS_STATIC) {
                        let previous_bottom_margin = margin_collapse_info.current_float_ceiling();
-                        flow::mut_base(kid).position.start.b = cur_b +
+                        kid.mut_base().position.start.b = cur_b +
-                            flow::base(kid).collapsible_margins
+                            kid.base().collapsible_margins
                                           .block_start_margin_for_noncollapsible_context() +
                            previous_bottom_margin
                    }
                    kid.place_float_if_applicable();
-                    if !flow::base(kid).flags.is_float() {
+                    if !kid.base().flags.is_float() {
                        kid.assign_block_size_for_inorder_child_if_necessary(layout_context,
                                                                             thread_id,
                                                                             content_box);
@ -852,10 +852,10 @@ impl BlockFlow {
                // Assign block-size now for the child if it might have floats in and we couldn't
                // before.
-                flow::mut_base(kid).floats = floats.clone();
+                kid.mut_base().floats = floats.clone();
-                if flow::base(kid).flags.is_float() {
+                if kid.base().flags.is_float() {
                    had_floated_children = true;
-                    flow::mut_base(kid).position.start.b = cur_b;
+                    kid.mut_base().position.start.b = cur_b;
                    {
                        let kid_block = kid.as_mut_block();
                        let float_ceiling = margin_collapse_info.current_float_ceiling();
@ -863,7 +863,7 @@ impl BlockFlow {
                    }
                    kid.place_float_if_applicable();
-                    let kid_base = flow::mut_base(kid);
+                    let kid_base = kid.mut_base();
                    floats = kid_base.floats.clone();
                    continue
                }
@ -875,8 +875,8 @@ impl BlockFlow {
                // complicated with margin collapse. Possibly the right thing to do is to lay out
                // the block again in this rare case. (Note that WebKit can lay blocks out twice;
                // this may be related, although I haven't looked into it closely.)
-                if flow::base(kid).flags.clears_floats() {
+                if kid.base().flags.clears_floats() {
-                    flow::mut_base(kid).floats = Floats::new(self.fragment.style.writing_mode)
+                    kid.mut_base().floats = Floats::new(self.fragment.style.writing_mode)
                }
                // Lay the child out if this was an in-order traversal.
@ -887,26 +887,26 @@ impl BlockFlow {
                if !had_children_with_clearance &&
                        floats.is_present() &&
-                        (flow::base(kid).flags.contains(FlowFlags::CLEARS_LEFT) ||
+                        (kid.base().flags.contains(FlowFlags::CLEARS_LEFT) ||
-                         flow::base(kid).flags.contains(FlowFlags::CLEARS_RIGHT)) {
+                         kid.base().flags.contains(FlowFlags::CLEARS_RIGHT)) {
                    had_children_with_clearance = true
                }
                // Handle any (possibly collapsed) top margin.
                let delta = margin_collapse_info.advance_block_start_margin(
-                    &flow::base(kid).collapsible_margins,
+                    &kid.base().collapsible_margins,
                    !had_children_with_clearance);
                translate_including_floats(&mut cur_b, delta, &mut floats);
                // Collapse-through margins should be placed at the top edge,
                // so we'll handle the delta after the bottom margin is processed
-                if let CollapsibleMargins::CollapseThrough(_) = flow::base(kid).collapsible_margins {
+                if let CollapsibleMargins::CollapseThrough(_) = kid.base().collapsible_margins {
                    cur_b = cur_b - delta;
                }
                // Clear past the floats that came in, if necessary.
-                let clearance = match (flow::base(kid).flags.contains(FlowFlags::CLEARS_LEFT),
+                let clearance = match (kid.base().flags.contains(FlowFlags::CLEARS_LEFT),
-                                       flow::base(kid).flags.contains(FlowFlags::CLEARS_RIGHT)) {
+                                       kid.base().flags.contains(FlowFlags::CLEARS_RIGHT)) {
                    (false, false) => Au(0),
                    (true, false) => floats.clearance(ClearType::Left),
                    (false, true) => floats.clearance(ClearType::Right),
@ -915,19 +915,19 @@ impl BlockFlow {
                translate_including_floats(&mut cur_b, clearance, &mut floats);
                // At this point, `cur_b` is at the border edge of the child.
-                flow::mut_base(kid).position.start.b = cur_b;
+                kid.mut_base().position.start.b = cur_b;
                // Now pull out the child's outgoing floats. We didn't do this immediately after
                // the `assign_block_size_for_inorder_child_if_necessary` call because clearance on
                // a block operates on the floats that come *in*, not the floats that go *out*.
                if need_to_process_child_floats {
-                    floats = flow::mut_base(kid).floats.clone()
+                    floats = kid.mut_base().floats.clone()
                }
                // Move past the child's border box. Do not use the `translate_including_floats`
                // function here because the child has already translated floats past its border
                // box.
-                let kid_base = flow::mut_base(kid);
+                let kid_base = kid.mut_base();
                cur_b = cur_b + kid_base.position.size.block;
                // Handle any (possibly collapsed) block-end margin.
@ -1371,11 +1371,11 @@ impl BlockFlow {
        let mut iterator = self.base.child_iter_mut().enumerate().peekable();
        while let Some((i, kid)) = iterator.next() {
-            flow::mut_base(kid).block_container_explicit_block_size = explicit_content_size;
+            kid.mut_base().block_container_explicit_block_size = explicit_content_size;
            // The inline-start margin edge of the child flow is at our inline-start content edge,
            // and its inline-size is our content inline-size.
-            let kid_mode = flow::base(kid).writing_mode;
+            let kid_mode = kid.base().writing_mode;
            {
                // Don't assign positions to children unless they're going to be reflowed.
                // Otherwise, the position we assign might be incorrect and never fixed up. (Issue
@ -1385,7 +1385,7 @@ impl BlockFlow {
                // `assign_block_size()`, which won't do anything unless `REFLOW` is set. So, if a
                // float child does not have `REFLOW` set, we must be careful to avoid touching its
                // inline position, as no logic will run afterward to set its true value.
-                let kid_base = flow::mut_base(kid);
+                let kid_base = kid.mut_base();
                let reflow_damage = if kid_base.flags.contains(FlowFlags::IS_ABSOLUTELY_POSITIONED) {
                    ServoRestyleDamage::REFLOW_OUT_OF_FLOW
                } else {
@ -1418,7 +1418,7 @@ impl BlockFlow {
            //
            // TODO(#2265, pcwalton): Do this in the cascade instead.
            let containing_block_text_align = self.fragment.style().get_inheritedtext().text_align;
-            flow::mut_base(kid).flags.set_text_align(containing_block_text_align);
+            kid.mut_base().flags.set_text_align(containing_block_text_align);
            // Handle `text-indent` on behalf of any inline children that we have. This is
            // necessary because any percentages are relative to the containing block, which only
@ -1554,7 +1554,7 @@ impl BlockFlow {
            // Assign final-final inline sizes on all our children.
            self.assign_inline_sizes(layout_context);
            // Re-run layout on our children.
-            for child in flow::mut_base(self).children.iter_mut() {
+            for child in self.base.child_iter_mut() {
                sequential::reflow(child, layout_context, RelayoutMode::Force);
            }
            // Assign our final-final block size.
@ -1597,7 +1597,7 @@ impl BlockFlow {
        } else {
            flags.remove(FlowFlags::CONTAINS_TEXT_OR_REPLACED_FRAGMENTS);
            for kid in self.base.children.iter() {
-                if flow::base(kid).flags.contains(FlowFlags::CONTAINS_TEXT_OR_REPLACED_FRAGMENTS) {
+                if kid.base().flags.contains(FlowFlags::CONTAINS_TEXT_OR_REPLACED_FRAGMENTS) {
                    flags.insert(FlowFlags::CONTAINS_TEXT_OR_REPLACED_FRAGMENTS);
                    break
                }
@ -1615,11 +1615,11 @@ impl BlockFlow {
        let (mut left_float_width_accumulator, mut right_float_width_accumulator) = (Au(0), Au(0));
        let mut preferred_inline_size_of_children_without_text_or_replaced_fragments = Au(0);
        for kid in self.base.child_iter_mut() {
-            if flow::base(kid).flags.contains(FlowFlags::IS_ABSOLUTELY_POSITIONED) || !consult_children {
+            if kid.base().flags.contains(FlowFlags::IS_ABSOLUTELY_POSITIONED) || !consult_children {
                continue
            }
-            let child_base = flow::mut_base(kid);
+            let child_base = kid.mut_base();
            let float_kind = child_base.flags.float_kind();
            computation.content_intrinsic_sizes.minimum_inline_size =
                max(computation.content_intrinsic_sizes.minimum_inline_size,
@ -1935,14 +1935,14 @@ impl Flow for BlockFlow {
                self.base.flags.contains(FlowFlags::MARGINS_CANNOT_COLLAPSE) {
            // Root element margins should never be collapsed according to CSS § 8.3.1.
            debug!("assign_block_size: assigning block_size for root flow {:?}",
-                   flow::base(self).debug_id());
+                   self.base().debug_id());
            self.assign_block_size_block_base(
                layout_context,
                fragmentation_context,
                MarginsMayCollapseFlag::MarginsMayNotCollapse)
        } else {
            debug!("assign_block_size: assigning block_size for block {:?}",
-                   flow::base(self).debug_id());
+                   self.base().debug_id());
            self.assign_block_size_block_base(
                layout_context,
                fragmentation_context,
@ -2060,9 +2060,9 @@ impl Flow for BlockFlow {
        // Process children.
        for kid in self.base.child_iter_mut() {
-            if flow::base(kid).flags.contains(FlowFlags::INLINE_POSITION_IS_STATIC) ||
+            if kid.base().flags.contains(FlowFlags::INLINE_POSITION_IS_STATIC) ||
-                    flow::base(kid).flags.contains(FlowFlags::BLOCK_POSITION_IS_STATIC) {
+                    kid.base().flags.contains(FlowFlags::BLOCK_POSITION_IS_STATIC) {
-                let kid_base = flow::mut_base(kid);
+                let kid_base = kid.mut_base();
                let physical_position = kid_base.position.to_physical(kid_base.writing_mode,
                                                                      container_size_for_children);
@ -2088,7 +2088,7 @@ impl Flow for BlockFlow {
                }
            }
-            flow::mut_base(kid).late_absolute_position_info =
+            kid.mut_base().late_absolute_position_info =
                late_absolute_position_info_for_children;
        }
    }
@ -2377,7 +2377,7 @@ pub trait ISizeAndMarginsComputer {
        // We also resize the block itself, to ensure that overflow is not calculated
        // as the inline-size of our parent. We might be smaller and we might be larger if we
        // overflow.
-        flow::mut_base(block).position.size.inline = inline_size + extra_inline_size_from_margin;
+        block.mut_base().position.size.inline = inline_size + extra_inline_size_from_margin;
    }
    /// Set the inline coordinate of the given flow if it is absolutely positioned.
--- a/components/layout/construct.rs
+++ b/components/layout/construct.rs
@ -19,7 +19,7 @@ use context::{LayoutContext, with_thread_local_font_context};
 use data::{LayoutDataFlags, LayoutData};
 use flex::FlexFlow;
 use floats::FloatKind;
-use flow::{self, AbsoluteDescendants, Flow, FlowClass, ImmutableFlowUtils};
+use flow::{AbsoluteDescendants, Flow, FlowClass, GetBaseFlow, ImmutableFlowUtils};
 use flow::{FlowFlags, MutableFlowUtils, MutableOwnedFlowUtils};
 use flow_ref::FlowRef;
 use fragment::{CanvasFragmentInfo, ImageFragmentInfo, InlineAbsoluteFragmentInfo, SvgFragmentInfo};
@ -96,7 +96,7 @@ impl ConstructionResult {
        match *self {
            ConstructionResult::None => 0,
            ConstructionResult::ConstructionItem(_) => 0,
-            ConstructionResult::Flow(ref flow_ref, _) => flow::base(&**flow_ref).debug_id(),
+            ConstructionResult::Flow(ref flow_ref, _) => flow_ref.base().debug_id(),
        }
    }
 }
@ -497,7 +497,7 @@ impl<'a, ConcreteThreadSafeLayoutNode: ThreadSafeLayoutNode>
                        ConstructionResult::Flow(kid_flow, AbsoluteDescendants::new());
                    self.set_flow_construction_result(&kid, construction_result)
                } else {
-                    if !flow::base(&*kid_flow).flags.contains(FlowFlags::IS_ABSOLUTELY_POSITIONED) {
+                    if !kid_flow.base().flags.contains(FlowFlags::IS_ABSOLUTELY_POSITIONED) {
                        // Flush any inline fragments that we were gathering up. This allows us to
                        // handle {ib} splits.
                        let old_inline_fragment_accumulator =
@ -625,7 +625,7 @@ impl<'a, ConcreteThreadSafeLayoutNode: ThreadSafeLayoutNode>
            flow.set_absolute_descendants(abs_descendants);
            abs_descendants = AbsoluteDescendants::new();
-            if flow::base(&*flow).flags.contains(FlowFlags::IS_ABSOLUTELY_POSITIONED) {
+            if flow.base().flags.contains(FlowFlags::IS_ABSOLUTELY_POSITIONED) {
                // This is now the only absolute flow in the subtree which hasn't yet
                // reached its CB.
                abs_descendants.push(flow.clone());
@ -780,7 +780,7 @@ impl<'a, ConcreteThreadSafeLayoutNode: ThreadSafeLayoutNode>
            match kid.get_construction_result() {
                ConstructionResult::None => {}
                ConstructionResult::Flow(flow, kid_abs_descendants) => {
-                    if !flow::base(&*flow).flags.contains(FlowFlags::IS_ABSOLUTELY_POSITIONED) {
+                    if !flow.base().flags.contains(FlowFlags::IS_ABSOLUTELY_POSITIONED) {
                        opt_inline_block_splits.push_back(InlineBlockSplit::new(
                            &mut fragment_accumulator, node, self.style_context(), flow));
                        abs_descendants.push_descendants(kid_abs_descendants);
@ -1073,7 +1073,7 @@ impl<'a, ConcreteThreadSafeLayoutNode: ThreadSafeLayoutNode>
            abs_descendants = AbsoluteDescendants::new();
-            if flow::base(&*flow).flags.contains(FlowFlags::IS_ABSOLUTELY_POSITIONED) {
+            if flow.base().flags.contains(FlowFlags::IS_ABSOLUTELY_POSITIONED) {
                // This is now the only absolute flow in the subtree which hasn't yet
                // reached its containing block.
                abs_descendants.push(flow.clone());
@ -1144,7 +1144,7 @@ impl<'a, ConcreteThreadSafeLayoutNode: ThreadSafeLayoutNode>
            abs_descendants = AbsoluteDescendants::new();
-            if flow::base(&*wrapper_flow).flags.contains(FlowFlags::IS_ABSOLUTELY_POSITIONED) {
+            if wrapper_flow.base().flags.contains(FlowFlags::IS_ABSOLUTELY_POSITIONED) {
                // This is now the only absolute flow in the subtree which hasn't yet
                // reached its containing block.
                abs_descendants.push(wrapper_flow.clone());
@ -1373,7 +1373,7 @@ impl<'a, ConcreteThreadSafeLayoutNode: ThreadSafeLayoutNode>
                    }
                    let flow = FlowRef::deref_mut(flow);
-                    flow::mut_base(flow).restyle_damage.insert(damage);
+                    flow.mut_base().restyle_damage.insert(damage);
                    flow.repair_style_and_bubble_inline_sizes(&style);
                    true
                }
@ -1398,7 +1398,7 @@ impl<'a, ConcreteThreadSafeLayoutNode: ThreadSafeLayoutNode>
                        match fragment.specific {
                            SpecificFragmentInfo::InlineBlock(ref mut inline_block_fragment) => {
                                let flow_ref = FlowRef::deref_mut(&mut inline_block_fragment.flow_ref);
-                                flow::mut_base(flow_ref).restyle_damage.insert(damage);
+                                flow_ref.mut_base().restyle_damage.insert(damage);
                                // FIXME(pcwalton): Fragment restyle damage too?
                                flow_ref.repair_style_and_bubble_inline_sizes(&style);
                            }
@ -1406,14 +1406,14 @@ impl<'a, ConcreteThreadSafeLayoutNode: ThreadSafeLayoutNode>
                                    ref mut inline_absolute_hypothetical_fragment) => {
                                let flow_ref = FlowRef::deref_mut(
                                    &mut inline_absolute_hypothetical_fragment.flow_ref);
-                                flow::mut_base(flow_ref).restyle_damage.insert(damage);
+                                flow_ref.mut_base().restyle_damage.insert(damage);
                                // FIXME(pcwalton): Fragment restyle damage too?
                                flow_ref.repair_style_and_bubble_inline_sizes(&style);
                            }
                            SpecificFragmentInfo::InlineAbsolute(ref mut inline_absolute_fragment) => {
                                let flow_ref = FlowRef::deref_mut(
                                    &mut inline_absolute_fragment.flow_ref);
-                                flow::mut_base(flow_ref).restyle_damage.insert(damage);
+                                flow_ref.mut_base().restyle_damage.insert(damage);
                                // FIXME(pcwalton): Fragment restyle damage too?
                                flow_ref.repair_style_and_bubble_inline_sizes(&style);
                            }
@ -1660,7 +1660,7 @@ impl<ConcreteThreadSafeLayoutNode> NodeUtils for ConcreteThreadSafeLayoutNode
    fn set_flow_construction_result(self, mut result: ConstructionResult) {
        if self.can_be_fragmented() {
            if let ConstructionResult::Flow(ref mut flow, _) = result {
-                flow::mut_base(FlowRef::deref_mut(flow)).flags.insert(FlowFlags::CAN_BE_FRAGMENTED);
+                FlowRef::deref_mut(flow).mut_base().flags.insert(FlowFlags::CAN_BE_FRAGMENTED);
            }
        }
@ -1732,11 +1732,11 @@ impl FlowConstructionUtils for FlowRef {
    /// Adds a new flow as a child of this flow. Fails if this flow is marked as a leaf.
    fn add_new_child(&mut self, mut new_child: FlowRef) {
        {
-            let kid_base = flow::mut_base(FlowRef::deref_mut(&mut new_child));
+            let kid_base = FlowRef::deref_mut(&mut new_child).mut_base();
            kid_base.parallel.parent = parallel::mut_owned_flow_to_unsafe_flow(self);
        }
-        let base = flow::mut_base(FlowRef::deref_mut(self));
+        let base = FlowRef::deref_mut(self).mut_base();
        base.children.push_back(new_child);
        let _ = base.parallel.children_count.fetch_add(1, Ordering::Relaxed);
    }
@ -1750,7 +1750,7 @@ impl FlowConstructionUtils for FlowRef {
    fn finish(&mut self) {
        if !opts::get().bubble_inline_sizes_separately {
            FlowRef::deref_mut(self).bubble_inline_sizes();
-            flow::mut_base(FlowRef::deref_mut(self)).restyle_damage.remove(ServoRestyleDamage::BUBBLE_ISIZES);
+            FlowRef::deref_mut(self).mut_base().restyle_damage.remove(ServoRestyleDamage::BUBBLE_ISIZES);
        }
    }
 }
@ -1951,7 +1951,7 @@ impl Legalizer {
            }
            (FlowClass::Flex, FlowClass::Inline) => {
-                flow::mut_base(FlowRef::deref_mut(child)).flags.insert(FlowFlags::MARGINS_CANNOT_COLLAPSE);
+                FlowRef::deref_mut(child).mut_base().flags.insert(FlowFlags::MARGINS_CANNOT_COLLAPSE);
                let mut block_wrapper =
                    Legalizer::create_anonymous_flow(context,
                                                     parent,
--- a/components/layout/display_list_builder.rs
+++ b/components/layout/display_list_builder.rs
@ -58,6 +58,7 @@ use style::computed_values::position::T as StylePosition;
 use style::computed_values::visibility::T as Visibility;
 use style::logical_geometry::{LogicalMargin, LogicalPoint, LogicalRect, LogicalSize, WritingMode};
 use style::properties::ComputedValues;
 use style::properties::longhands::background_origin::single_value::computed_value::T as BackgroundOrigin;
 use style::properties::longhands::border_image_repeat::computed_value::RepeatKeyword;
 use style::properties::style_structs;
 use style::servo::restyle_damage::ServoRestyleDamage;
@ -503,30 +504,16 @@ pub trait FragmentDisplayListBuilding {
                                             size: Size2D<Au>)
                                             -> Option<WebRenderImageInfo>;
    fn convert_linear_gradient(&self,
                               bounds: &Rect<Au>,
                               stops: &[GradientItem],
                               direction: &LineDirection,
                               repeating: bool)
                               -> display_list::Gradient;
    fn convert_radial_gradient(&self,
                               bounds: &Rect<Au>,
                               stops: &[GradientItem],
                               shape: &EndingShape,
                               center: &Position,
                               repeating: bool)
                               -> display_list::RadialGradient;
    /// Adds the display items necessary to paint the background linear gradient of this fragment
    /// to the appropriate section of the display list.
    fn build_display_list_for_background_gradient(&self,
                                                  state: &mut DisplayListBuildState,
                                                  display_list_section: DisplayListSection,
-                                                  absolute_bounds: &Rect<Au>,
+                                                  absolute_bounds: Rect<Au>,
                                                  clip: &LocalClip,
                                                  gradient: &Gradient,
-                                                  style: &ComputedValues);
+                                                  style: &ComputedValues,
                                                  index: usize);
    /// Adds the display items necessary to paint the borders of this fragment to a display list if
    /// necessary.
@ -819,6 +806,120 @@ fn convert_gradient_stops(gradient_items: &[GradientItem],
    stops
 }
 fn convert_linear_gradient(size: Size2D<Au>,
                           stops: &[GradientItem],
                           direction: LineDirection,
                           repeating: bool)
                           -> display_list::Gradient {
    let angle = match direction {
        LineDirection::Angle(angle) => angle.radians(),
        LineDirection::Horizontal(x) => {
            match x {
                X::Left => Angle::Deg(270.).radians(),
                X::Right => Angle::Deg(90.).radians(),
            }
        },
        LineDirection::Vertical(y) => {
            match y {
                Y::Top => Angle::Deg(0.).radians(),
                Y::Bottom => Angle::Deg(180.).radians(),
            }
        },
        LineDirection::Corner(horizontal, vertical) => {
            // This the angle for one of the diagonals of the box. Our angle
            // will either be this one, this one + PI, or one of the other
            // two perpendicular angles.
            let atan = (size.height.to_f32_px() /
                        size.width.to_f32_px()).atan();
            match (horizontal, vertical) {
                (X::Right, Y::Bottom)
                    => f32::consts::PI - atan,
                (X::Left, Y::Bottom)
                    => f32::consts::PI + atan,
                (X::Right, Y::Top)
                    => atan,
                (X::Left, Y::Top)
                    => -atan,
            }
        }
    };
    // Get correct gradient line length, based on:
    // https://drafts.csswg.org/css-images-3/#linear-gradients
    let dir = Point2D::new(angle.sin(), -angle.cos());
    let line_length = (dir.x * size.width.to_f32_px()).abs() +
                        (dir.y * size.height.to_f32_px()).abs();
    let inv_dir_length = 1.0 / (dir.x * dir.x + dir.y * dir.y).sqrt();
    // This is the vector between the center and the ending point; i.e. half
    // of the distance between the starting point and the ending point.
    let delta = Vector2D::new(Au::from_f32_px(dir.x * inv_dir_length * line_length / 2.0),
                                Au::from_f32_px(dir.y * inv_dir_length * line_length / 2.0));
    // This is the length of the gradient line.
    let length = Au::from_f32_px(
        (delta.x.to_f32_px() * 2.0).hypot(delta.y.to_f32_px() * 2.0));
    let mut stops = convert_gradient_stops(stops, length);
    // Only clamped gradients need to be fixed because in repeating gradients
    // there is no "first" or "last" stop because they repeat infinitly in
    // both directions, so the rendering is always correct.
    if !repeating {
        fix_gradient_stops(&mut stops);
    }
    let center = Point2D::new(size.width / 2, size.height / 2);
    display_list::Gradient {
        start_point: center - delta,
        end_point: center + delta,
        stops: stops,
        repeating: repeating,
    }
 }
 fn convert_radial_gradient(size: Size2D<Au>,
                           stops: &[GradientItem],
                           shape: EndingShape,
                           center: Position,
                           repeating: bool)
                           -> display_list::RadialGradient {
    let center = Point2D::new(center.horizontal.to_used_value(size.width),
                                center.vertical.to_used_value(size.height));
    let radius = match shape {
        GenericEndingShape::Circle(Circle::Radius(length)) => {
            let length = Au::from(length);
            Size2D::new(length, length)
        },
        GenericEndingShape::Circle(Circle::Extent(extent)) => {
            convert_circle_size_keyword(extent, &size, &center)
        },
        GenericEndingShape::Ellipse(Ellipse::Radii(x, y)) => {
            Size2D::new(x.to_used_value(size.width), y.to_used_value(size.height))
        },
        GenericEndingShape::Ellipse(Ellipse::Extent(extent)) => {
            convert_ellipse_size_keyword(extent, &size, &center)
        },
    };
    let mut stops = convert_gradient_stops(stops, radius.width);
    // Repeating gradients have no last stops that can be ignored. So
    // fixup is not necessary but may actually break the gradient.
    if !repeating {
        fix_gradient_stops(&mut stops);
    }
    display_list::RadialGradient {
        center: center,
        radius: radius,
        stops: stops,
        repeating: repeating,
    }
 }
 #[inline]
 /// Duplicate the first and last stops if necessary.
 ///
@ -1023,10 +1124,11 @@ impl FragmentDisplayListBuilding for Fragment {
                Either::Second(Image::Gradient(ref gradient)) => {
                    self.build_display_list_for_background_gradient(state,
                                                                    display_list_section,
-                                                                    &absolute_bounds,
+                                                                    *absolute_bounds,
                                                                    &clip,
                                                                    gradient,
-                                                                    style);
+                                                                    style,
                                                                    i);
                }
                Either::Second(Image::Url(ref image_url)) => {
                    if let Some(url) = image_url.url() {
@ -1310,162 +1412,112 @@ impl FragmentDisplayListBuilding for Fragment {
        Some(webrender_image)
    }
    fn convert_linear_gradient(&self,
                               bounds: &Rect<Au>,
                               stops: &[GradientItem],
                               direction: &LineDirection,
                               repeating: bool)
                               -> display_list::Gradient {
        let angle = match *direction {
            LineDirection::Angle(angle) => angle.radians(),
            LineDirection::Horizontal(x) => {
                match x {
                    X::Left => Angle::Deg(270.).radians(),
                    X::Right => Angle::Deg(90.).radians(),
                }
            },
            LineDirection::Vertical(y) => {
                match y {
                    Y::Top => Angle::Deg(0.).radians(),
                    Y::Bottom => Angle::Deg(180.).radians(),
                }
            },
            LineDirection::Corner(horizontal, vertical) => {
                // This the angle for one of the diagonals of the box. Our angle
                // will either be this one, this one + PI, or one of the other
                // two perpendicular angles.
                let atan = (bounds.size.height.to_f32_px() /
                            bounds.size.width.to_f32_px()).atan();
                match (horizontal, vertical) {
                    (X::Right, Y::Bottom)
                        => f32::consts::PI - atan,
                    (X::Left, Y::Bottom)
                        => f32::consts::PI + atan,
                    (X::Right, Y::Top)
                        => atan,
                    (X::Left, Y::Top)
                        => -atan,
                }
            }
        };
        // Get correct gradient line length, based on:
        // https://drafts.csswg.org/css-images-3/#linear-gradients
        let dir = Point2D::new(angle.sin(), -angle.cos());
        let line_length = (dir.x * bounds.size.width.to_f32_px()).abs() +
                          (dir.y * bounds.size.height.to_f32_px()).abs();
        let inv_dir_length = 1.0 / (dir.x * dir.x + dir.y * dir.y).sqrt();
        // This is the vector between the center and the ending point; i.e. half
        // of the distance between the starting point and the ending point.
        let delta = Vector2D::new(Au::from_f32_px(dir.x * inv_dir_length * line_length / 2.0),
                                  Au::from_f32_px(dir.y * inv_dir_length * line_length / 2.0));
        // This is the length of the gradient line.
        let length = Au::from_f32_px(
            (delta.x.to_f32_px() * 2.0).hypot(delta.y.to_f32_px() * 2.0));
        let mut stops = convert_gradient_stops(stops, length);
        // Only clamped gradients need to be fixed because in repeating gradients
        // there is no "first" or "last" stop because they repeat infinitly in
        // both directions, so the rendering is always correct.
        if !repeating {
            fix_gradient_stops(&mut stops);
        }
        let center = Point2D::new(bounds.size.width / 2, bounds.size.height / 2);
        display_list::Gradient {
            start_point: center - delta,
            end_point: center + delta,
            stops: stops,
            repeating: repeating,
        }
    }
    fn convert_radial_gradient(&self,
                               bounds: &Rect<Au>,
                               stops: &[GradientItem],
                               shape: &EndingShape,
                               center: &Position,
                               repeating: bool)
                               -> display_list::RadialGradient {
        let center = Point2D::new(center.horizontal.to_used_value(bounds.size.width),
                                  center.vertical.to_used_value(bounds.size.height));
        let radius = match *shape {
            GenericEndingShape::Circle(Circle::Radius(length)) => {
                let length = Au::from(length);
                Size2D::new(length, length)
            },
            GenericEndingShape::Circle(Circle::Extent(extent)) => {
                convert_circle_size_keyword(extent, &bounds.size, &center)
            },
            GenericEndingShape::Ellipse(Ellipse::Radii(x, y)) => {
                Size2D::new(x.to_used_value(bounds.size.width), y.to_used_value(bounds.size.height))
            },
            GenericEndingShape::Ellipse(Ellipse::Extent(extent)) => {
                convert_ellipse_size_keyword(extent, &bounds.size, &center)
            },
        };
        let mut stops = convert_gradient_stops(stops, radius.width);
        // Repeating gradients have no last stops that can be ignored. So
        // fixup is not necessary but may actually break the gradient.
        if !repeating {
            fix_gradient_stops(&mut stops);
        }
        display_list::RadialGradient {
            center: center,
            radius: radius,
            stops: stops,
            repeating: repeating,
        }
    }
    fn build_display_list_for_background_gradient(&self,
                                                  state: &mut DisplayListBuildState,
                                                  display_list_section: DisplayListSection,
-                                                  absolute_bounds: &Rect<Au>,
+                                                  absolute_bounds: Rect<Au>,
                                                  clip: &LocalClip,
                                                  gradient: &Gradient,
-                                                  style: &ComputedValues) {
+                                                  style: &ComputedValues,
-        let border = self.border_width().to_physical(style.writing_mode);
+                                                  index: usize) {
-        let mut bounds = *absolute_bounds;
+        // Calculate where the first "tile" needs to be placed on one axis.
-        bounds.origin.x = bounds.origin.x + border.left;
+        // * base is the beginning of the visible area
-        bounds.origin.y = bounds.origin.y + border.top;
+        // * start is the current "tile" position
-        bounds.size.width = bounds.size.width - border.horizontal();
+        // * tile is the length of the "tile"
-        bounds.size.height = bounds.size.height - border.vertical();
+        // Returns a difference between start and new start.
        // It holds that base - tile < start - diff <= base
        fn get_first_tile(base: Au, start: Au, tile: Au) -> Au {
            if tile == Au(0) {
                return Au(0);
            }
            if start > base {
                ((start - base) / tile + 1) * tile
            } else {
                ((base - start) / tile) * tile
            }
        }
-        let base = state.create_base_display_item(&bounds,
+        let bg = style.get_background();
        let bg_origin = get_cyclic(&bg.background_origin.0, index).clone();
        let bg_size = get_cyclic(&bg.background_size.0, index).clone();
        let bg_position_x = get_cyclic(&bg.background_position_x.0, index).clone();
        let bg_position_y = get_cyclic(&bg.background_position_y.0, index).clone();
        let mut bounds = absolute_bounds;
        match bg_origin {
            BackgroundOrigin::BorderBox => {}
            BackgroundOrigin::PaddingBox => {
                let border = style.logical_border_width().to_physical(style.writing_mode);
                bounds.origin.x += border.left;
                bounds.origin.y += border.top;
                bounds.size.width -= border.horizontal();
                bounds.size.height -= border.vertical();
            }
            BackgroundOrigin::ContentBox => {
                let border_padding = self.border_padding.to_physical(style.writing_mode);
                bounds.origin.x += border_padding.left;
                bounds.origin.y += border_padding.top;
                bounds.size.width -= border_padding.horizontal();
                bounds.size.height -= border_padding.vertical();
            }
        }
        bounds.origin.x += bg_position_x.to_used_value(bounds.size.width);
        bounds.origin.y += bg_position_y.to_used_value(bounds.size.height);
        let tile = match bg_size {
            BackgroundSize::Cover | BackgroundSize::Contain => bounds.size,
            BackgroundSize::Explicit { width, height } => {
                Size2D::new(
                    MaybeAuto::from_style(width, bounds.size.width)
                        .specified_or_default(bounds.size.width),
                    MaybeAuto::from_style(height, bounds.size.height)
                        .specified_or_default(bounds.size.height))
            }
        };
        let diff_x = get_first_tile(absolute_bounds.origin.x,
                                    bounds.origin.x,
                                    tile.width);
        let diff_y = get_first_tile(absolute_bounds.origin.y,
                                    bounds.origin.y,
                                    tile.height);
        let tiled_bounds = Rect::new(
            Point2D::new(bounds.origin.x - diff_x, bounds.origin.y - diff_y),
            Size2D::new(absolute_bounds.size.width + diff_x,
                        absolute_bounds.size.height + diff_y));
        let base = state.create_base_display_item(&tiled_bounds,
                                                  *clip,
                                                  self.node,
                                                  style.get_cursor(Cursor::Default),
                                                  display_list_section);
        let display_item = match gradient.kind {
-            GradientKind::Linear(ref angle_or_corner) => {
+            GradientKind::Linear(angle_or_corner) => {
-                let gradient = self.convert_linear_gradient(&bounds,
+                let gradient = convert_linear_gradient(
-                                                            &gradient.items[..],
+                    tile,
-                                                            angle_or_corner,
+                    &gradient.items[..],
-                                                            gradient.repeating);
+                    angle_or_corner,
                    gradient.repeating);
                DisplayItem::Gradient(Box::new(GradientDisplayItem {
                    base: base,
                    gradient: gradient,
                    tile: tile,
                }))
            }
-            GradientKind::Radial(ref shape, ref center, _angle) => {
+            GradientKind::Radial(shape, center, _angle) => {
-                let gradient = self.convert_radial_gradient(&bounds,
+                let gradient = convert_radial_gradient(
-                                                            &gradient.items[..],
+                    tile,
-                                                            shape,
+                    &gradient.items[..],
-                                                            center,
+                    shape,
-                                                            gradient.repeating);
+                    center,
                    gradient.repeating);
                DisplayItem::RadialGradient(Box::new(RadialGradientDisplayItem {
                    base: base,
                    gradient: gradient,
                    tile: tile,
                }))
            }
        };
@ -1594,10 +1646,10 @@ impl FragmentDisplayListBuilding for Fragment {
            Either::Second(Image::Gradient(ref gradient)) => {
                match gradient.kind {
                    GradientKind::Linear(angle_or_corner) => {
-                        let grad = self.convert_linear_gradient(&bounds,
+                        let grad = convert_linear_gradient(bounds.size,
-                                                                &gradient.items[..],
+                                                           &gradient.items[..],
-                                                                &angle_or_corner,
+                                                           angle_or_corner,
-                                                                gradient.repeating);
+                                                           gradient.repeating);
                        state.add_display_item(DisplayItem::Border(Box::new(BorderDisplayItem {
                            base: base,
@ -1610,12 +1662,12 @@ impl FragmentDisplayListBuilding for Fragment {
                            }),
                        })));
                    }
-                    GradientKind::Radial(ref shape, ref center, _angle) => {
+                    GradientKind::Radial(shape, center, _angle) => {
-                        let grad = self.convert_radial_gradient(&bounds,
+                        let grad = convert_radial_gradient(bounds.size,
-                                                                &gradient.items[..],
+                                                           &gradient.items[..],
-                                                                shape,
+                                                           shape,
-                                                                center,
+                                                           center,
-                                                                gradient.repeating);
+                                                           gradient.repeating);
                        state.add_display_item(DisplayItem::Border(Box::new(BorderDisplayItem {
                            base: base,
                            border_widths: border.to_physical(style.writing_mode),
@ -1700,7 +1752,7 @@ impl FragmentDisplayListBuilding for Fragment {
                                                    style: &ComputedValues,
                                                    bounds: &Rect<Au>,
                                                    clip: &Rect<Au>) {
-        use style::values::Either;
+        use style::values::specified::outline::OutlineStyle;
        let width = Au::from(style.get_outline().outline_width);
        if width == Au(0) {
@ -1708,9 +1760,9 @@ impl FragmentDisplayListBuilding for Fragment {
        }
        let outline_style = match style.get_outline().outline_style {
-            Either::First(_auto) => BorderStyle::Solid,
+            OutlineStyle::Auto => BorderStyle::Solid,
-            Either::Second(BorderStyle::None) => return,
+            OutlineStyle::Other(BorderStyle::None) => return,
-            Either::Second(border_style) => border_style
+            OutlineStyle::Other(border_style) => border_style
        };
        // Outlines are not accounted for in the dimensions of the border box, so adjust the
--- a/components/layout/flex.rs
+++ b/components/layout/flex.rs
@ -13,8 +13,7 @@ use display_list_builder::{DisplayListBuildState, FlexFlowDisplayListBuilding};
 use display_list_builder::StackingContextCollectionState;
 use euclid::Point2D;
 use floats::FloatKind;
-use flow;
+use flow::{Flow, FlowClass, GetBaseFlow, ImmutableFlowUtils, OpaqueFlow, FlowFlags};
 use flow::{Flow, FlowClass, ImmutableFlowUtils, OpaqueFlow, FlowFlags};
 use fragment::{Fragment, FragmentBorderBoxIterator, Overflow};
 use layout_debug;
 use model::{AdjoiningMargins, CollapsibleMargins};
@ -451,7 +450,7 @@ impl FlexFlow {
        let mut computation = self.block_flow.fragment.compute_intrinsic_inline_sizes();
        if !fixed_width {
            for kid in self.block_flow.base.children.iter_mut() {
-                let base = flow::mut_base(kid);
+                let base = kid.mut_base();
                let is_absolutely_positioned = base.flags.contains(FlowFlags::IS_ABSOLUTELY_POSITIONED);
                if !is_absolutely_positioned {
                    let flex_item_inline_sizes = IntrinsicISizes {
@ -477,7 +476,7 @@ impl FlexFlow {
        let mut computation = self.block_flow.fragment.compute_intrinsic_inline_sizes();
        if !fixed_width {
            for kid in self.block_flow.base.children.iter_mut() {
-                let base = flow::mut_base(kid);
+                let base = kid.mut_base();
                let is_absolutely_positioned = base.flags.contains(FlowFlags::IS_ABSOLUTELY_POSITIONED);
                if !is_absolutely_positioned {
                    computation.content_intrinsic_sizes.minimum_inline_size =
@ -519,7 +518,7 @@ impl FlexFlow {
        let mut children = self.block_flow.base.children.random_access_mut();
        for kid in &mut self.items {
-            let kid_base = flow::mut_base(children.get(kid.index));
+            let kid_base = children.get(kid.index).mut_base();
            kid_base.block_container_explicit_block_size = container_block_size;
            if kid_base.flags.contains(FlowFlags::INLINE_POSITION_IS_STATIC) {
                // The inline-start margin edge of the child flow is at our inline-start content
@ -667,7 +666,7 @@ impl FlexFlow {
        let mut children = self.block_flow.base.children.random_access_mut();
        for item in &mut self.items {
-            let base = flow::mut_base(children.get(item.index));
+            let base = children.get(item.index).mut_base();
            if !self.main_reverse {
                base.position.start.b = cur_b;
                cur_b = cur_b + base.position.size.block;
--- a/components/layout/floats.rs
+++ b/components/layout/floats.rs
@ -4,7 +4,7 @@
 use app_units::{Au, MAX_AU};
 use block::FormattingContextType;
-use flow::{self, Flow, FlowFlags, ImmutableFlowUtils};
+use flow::{Flow, FlowFlags, GetBaseFlow, ImmutableFlowUtils};
 use persistent_list::PersistentList;
 use std::cmp::{max, min};
 use std::fmt;
@ -458,7 +458,7 @@ impl SpeculatedFloatPlacement {
    /// Given the speculated inline size of the floats out for the inorder predecessor of this
    /// flow, computes the speculated inline size of the floats flowing in.
    pub fn compute_floats_in(&mut self, flow: &mut Flow) {
-        let base_flow = flow::base(flow);
+        let base_flow = flow.base();
        if base_flow.flags.contains(FlowFlags::CLEARS_LEFT) {
            self.left = Au(0)
        }
@ -491,7 +491,7 @@ impl SpeculatedFloatPlacement {
            }
        }
-        let base_flow = flow::base(flow);
+        let base_flow = flow.base();
        if !base_flow.flags.is_float() {
            return
        }
@ -522,7 +522,7 @@ impl SpeculatedFloatPlacement {
    /// Given a flow, computes the speculated inline size of the floats in of its first child.
    pub fn compute_floats_in_for_first_child(parent_flow: &mut Flow) -> SpeculatedFloatPlacement {
        if !parent_flow.is_block_like() {
-            return flow::base(parent_flow).speculated_float_placement_in
+            return parent_flow.base().speculated_float_placement_in
        }
        let parent_block_flow = parent_flow.as_block();
--- a/components/layout/flow.rs
+++ b/components/layout/flow.rs
@ -76,6 +76,30 @@ use table_wrapper::TableWrapperFlow;
 #[allow(unsafe_code)]
 pub unsafe trait HasBaseFlow {}
 /// Methods to get the `BaseFlow` from any `HasBaseFlow` type.
 pub trait GetBaseFlow {
    fn base(&self) -> &BaseFlow;
    fn mut_base(&mut self) -> &mut BaseFlow;
 }
 impl<T: HasBaseFlow + ?Sized> GetBaseFlow for T {
    #[inline(always)]
    #[allow(unsafe_code)]
    fn base(&self) -> &BaseFlow {
        let ptr: *const Self = self;
        let ptr = ptr as *const BaseFlow;
        unsafe { &*ptr }
    }
    #[inline(always)]
    #[allow(unsafe_code)]
    fn mut_base(&mut self) -> &mut BaseFlow {
        let ptr: *mut Self = self;
        let ptr = ptr as *mut BaseFlow;
        unsafe { &mut *ptr }
    }
 }
 /// Virtual methods that make up a float context.
 ///
 /// Note that virtual methods have a cost; we should not overuse them in Servo. Consider adding
@ -224,8 +248,8 @@ pub trait Flow: HasBaseFlow + fmt::Debug + Sync + Send + 'static {
                layout_context: &LayoutContext,
                _fragmentation_context: Option<FragmentationContext>)
                -> Option<Arc<Flow>> {
-        fn recursive_assign_block_size<F: ?Sized + Flow>(flow: &mut F, ctx: &LayoutContext) {
+        fn recursive_assign_block_size<F: ?Sized + Flow + GetBaseFlow>(flow: &mut F, ctx: &LayoutContext) {
-            for child in mut_base(flow).children.iter_mut() {
+            for child in flow.mut_base().child_iter_mut() {
                recursive_assign_block_size(child, ctx)
            }
            flow.assign_block_size(ctx);
@ -251,12 +275,12 @@ pub trait Flow: HasBaseFlow + fmt::Debug + Sync + Send + 'static {
                                                        parent_thread_id: u8,
                                                        _content_box: LogicalRect<Au>)
                                                        -> bool {
-        let might_have_floats_in_or_out = base(self).might_have_floats_in() ||
+        let might_have_floats_in_or_out = self.base().might_have_floats_in() ||
-            base(self).might_have_floats_out();
+            self.base().might_have_floats_out();
        if might_have_floats_in_or_out {
-            mut_base(self).thread_id = parent_thread_id;
+            self.mut_base().thread_id = parent_thread_id;
            self.assign_block_size(layout_context);
-            mut_base(self).restyle_damage.remove(ServoRestyleDamage::REFLOW_OUT_OF_FLOW | ServoRestyleDamage::REFLOW);
+            self.mut_base().restyle_damage.remove(ServoRestyleDamage::REFLOW_OUT_OF_FLOW | ServoRestyleDamage::REFLOW);
        }
        might_have_floats_in_or_out
    }
@ -264,9 +288,9 @@ pub trait Flow: HasBaseFlow + fmt::Debug + Sync + Send + 'static {
    fn get_overflow_in_parent_coordinates(&self) -> Overflow {
        // FIXME(#2795): Get the real container size.
        let container_size = Size2D::zero();
-        let position = base(self).position.to_physical(base(self).writing_mode, container_size);
+        let position = self.base().position.to_physical(self.base().writing_mode, container_size);
-        let mut overflow = base(self).overflow;
+        let mut overflow = self.base().overflow;
        match self.class() {
            FlowClass::Block | FlowClass::TableCaption | FlowClass::TableCell => {}
@ -277,9 +301,9 @@ pub trait Flow: HasBaseFlow + fmt::Debug + Sync + Send + 'static {
        }
        let border_box = self.as_block().fragment.stacking_relative_border_box(
-            &base(self).stacking_relative_position,
+            &self.base().stacking_relative_position,
-            &base(self).early_absolute_position_info.relative_containing_block_size,
+            &self.base().early_absolute_position_info.relative_containing_block_size,
-            base(self).early_absolute_position_info.relative_containing_block_mode,
+            self.base().early_absolute_position_info.relative_containing_block_mode,
            CoordinateSystem::Own);
        if StyleOverflow::Visible != self.as_block().fragment.style.get_box().overflow_x {
            overflow.paint.origin.x = Au(0);
@ -341,13 +365,13 @@ pub trait Flow: HasBaseFlow + fmt::Debug + Sync + Send + 'static {
            FlowClass::Block |
            FlowClass::TableCaption |
            FlowClass::TableCell => {
-                for kid in mut_base(self).children.iter_mut() {
+                for kid in self.mut_base().children.iter_mut() {
                    overflow.union(&kid.get_overflow_in_parent_coordinates());
                }
            }
            _ => {}
        }
-        mut_base(self).overflow = overflow
+        self.mut_base().overflow = overflow
    }
    /// Phase 4 of reflow: Compute the stacking-relative position (origin of the content box,
@ -406,7 +430,7 @@ pub trait Flow: HasBaseFlow + fmt::Debug + Sync + Send + 'static {
    fn contains_positioned_fragments(&self) -> bool {
        self.contains_relatively_positioned_fragments() ||
-            base(self).flags.contains(FlowFlags::IS_ABSOLUTELY_POSITIONED)
+            self.base().flags.contains(FlowFlags::IS_ABSOLUTELY_POSITIONED)
    }
    fn contains_relatively_positioned_fragments(&self) -> bool {
@ -448,41 +472,13 @@ pub trait Flow: HasBaseFlow + fmt::Debug + Sync + Send + 'static {
    fn print_extra_flow_children(&self, _: &mut PrintTree) { }
    fn clipping_and_scrolling(&self) -> ClippingAndScrolling {
-        match base(self).clipping_and_scrolling {
+        match self.base().clipping_and_scrolling {
            Some(info) => info,
            None => unreachable!("Tried to access scroll root id on Flow before assignment"),
        }
    }
 }
 // Base access
 #[inline(always)]
 #[allow(unsafe_code)]
 pub fn base<T: ?Sized + HasBaseFlow>(this: &T) -> &BaseFlow {
    let ptr: *const T = this;
    let ptr = ptr as *const BaseFlow;
    unsafe { &*ptr }
 }
 /// Iterates over the children of this immutable flow.
 pub fn child_iter<'a>(flow: &'a Flow) -> FlowListIterator {
    base(flow).children.iter()
 }
 #[inline(always)]
 #[allow(unsafe_code)]
 pub fn mut_base<T: ?Sized + HasBaseFlow>(this: &mut T) -> &mut BaseFlow {
    let ptr: *mut T = this;
    let ptr = ptr as *mut BaseFlow;
    unsafe { &mut *ptr }
 }
 /// Iterates over the children of this flow.
 pub fn child_iter_mut<'a>(flow: &'a mut Flow) -> MutFlowListIterator<'a> {
    mut_base(flow).children.iter_mut()
 }
 pub trait ImmutableFlowUtils {
    // Convenience functions
@ -1106,6 +1102,11 @@ impl BaseFlow {
        }
    }
    /// Iterates over the children of this immutable flow.
    pub fn child_iter(&self) -> FlowListIterator {
        self.children.iter()
    }
    pub fn child_iter_mut(&mut self) -> MutFlowListIterator {
        self.children.iter_mut()
    }
@ -1216,12 +1217,12 @@ impl<'a> ImmutableFlowUtils for &'a Flow {
    /// Returns true if this flow has no children.
    fn is_leaf(self) -> bool {
-        base(self).children.is_empty()
+        self.base().children.is_empty()
    }
    /// Returns the number of children that this flow possesses.
    fn child_count(self) -> usize {
-        base(self).children.len()
+        self.base().children.len()
    }
    /// Return true if this flow is a Block Container.
@ -1267,14 +1268,14 @@ impl<'a> ImmutableFlowUtils for &'a Flow {
    fn print_with_tree(self, print_tree: &mut PrintTree) {
        print_tree.new_level(format!("{:?}", self));
        self.print_extra_flow_children(print_tree);
-        for kid in child_iter(self) {
+        for kid in self.base().child_iter() {
            kid.print_with_tree(print_tree);
        }
        print_tree.end_level();
    }
    fn floats_might_flow_through(self) -> bool {
-        if !base(self).might_have_floats_in() && !base(self).might_have_floats_out() {
+        if !self.base().might_have_floats_in() && !self.base().might_have_floats_out() {
            return false
        }
        if self.is_root() {
@ -1287,15 +1288,15 @@ impl<'a> ImmutableFlowUtils for &'a Flow {
    }
    fn baseline_offset_of_last_line_box_in_flow(self) -> Option<Au> {
-        for kid in base(self).children.iter().rev() {
+        for kid in self.base().children.iter().rev() {
            if kid.is_inline_flow() {
                if let Some(baseline_offset) = kid.as_inline().baseline_offset_of_last_line() {
-                    return Some(base(kid).position.start.b + baseline_offset)
+                    return Some(kid.base().position.start.b + baseline_offset)
                }
            }
-            if kid.is_block_like() && !base(kid).flags.contains(FlowFlags::IS_ABSOLUTELY_POSITIONED) {
+            if kid.is_block_like() && !kid.base().flags.contains(FlowFlags::IS_ABSOLUTELY_POSITIONED) {
                if let Some(baseline_offset) = kid.baseline_offset_of_last_line_box_in_flow() {
-                    return Some(base(kid).position.start.b + baseline_offset)
+                    return Some(kid.base().position.start.b + baseline_offset)
                }
            }
        }
@ -1308,7 +1309,7 @@ impl<'a> MutableFlowUtils for &'a mut Flow {
    /// calling them individually, since there is no reason not to perform both operations.
    fn repair_style_and_bubble_inline_sizes(self, style: &::ServoArc<ComputedValues>) {
        self.repair_style(style);
-        mut_base(self).update_flags_if_needed(style);
+        self.mut_base().update_flags_if_needed(style);
        self.bubble_inline_sizes();
    }
 }
@ -1323,11 +1324,11 @@ impl MutableOwnedFlowUtils for FlowRef {
    /// construction is allowed to possess.
    fn set_absolute_descendants(&mut self, abs_descendants: AbsoluteDescendants) {
        let this = self.clone();
-        let base = mut_base(FlowRef::deref_mut(self));
+        let base = FlowRef::deref_mut(self).mut_base();
        base.abs_descendants = abs_descendants;
        for descendant_link in base.abs_descendants.descendant_links.iter_mut() {
            debug_assert!(!descendant_link.has_reached_containing_block);
-            let descendant_base = mut_base(FlowRef::deref_mut(&mut descendant_link.flow));
+            let descendant_base = FlowRef::deref_mut(&mut descendant_link.flow).mut_base();
            descendant_base.absolute_cb.set(this.clone());
        }
    }
@ -1353,10 +1354,10 @@ impl MutableOwnedFlowUtils for FlowRef {
        });
        let this = self.clone();
-        let base = mut_base(FlowRef::deref_mut(self));
+        let base = FlowRef::deref_mut(self).mut_base();
        base.abs_descendants = applicable_absolute_descendants;
        for descendant_link in base.abs_descendants.iter() {
-            let descendant_base = mut_base(descendant_link);
+            let descendant_base = descendant_link.mut_base();
            descendant_base.absolute_cb.set(this.clone());
        }
    }
--- a/components/layout/fragment.rs
+++ b/components/layout/fragment.rs
@ -12,7 +12,7 @@ use canvas_traits::canvas::CanvasMsg;
 use context::{LayoutContext, with_thread_local_font_context};
 use euclid::{Transform3D, Point2D, Vector2D, Rect, Size2D};
 use floats::ClearType;
-use flow::{self, ImmutableFlowUtils};
+use flow::{GetBaseFlow, ImmutableFlowUtils};
 use flow_ref::FlowRef;
 use gfx;
 use gfx::display_list::{BLUR_INFLATION_FACTOR, OpaqueNode};
@ -232,7 +232,7 @@ impl SpecificFragmentInfo {
                SpecificFragmentInfo::InlineBlock(ref info) => &info.flow_ref,
            };
-        flow::base(&**flow).restyle_damage
+        flow.base().restyle_damage
    }
    pub fn get_type(&self) -> &'static str {
@ -1750,22 +1750,17 @@ impl Fragment {
        let character_breaking_strategy =
            text_fragment_info.run.character_slices_in_range(&text_fragment_info.range);
-        match self.calculate_split_position_using_breaking_strategy(character_breaking_strategy,
+
-                                                                    max_inline_size,
+        let split_info = self.calculate_split_position_using_breaking_strategy(
-                                                                    SplitOptions::empty()) {
+                character_breaking_strategy,
-            None => None,
+                max_inline_size,
-            Some(split_info) => {
+                SplitOptions::empty())?;
-                match split_info.inline_start {
+
-                    None => None,
+        let split = split_info.inline_start?;
-                    Some(split) => {
+        Some(TruncationResult {
-                        Some(TruncationResult {
+            split: split,
-                            split: split,
+            text_run: split_info.text_run.clone(),
-                            text_run: split_info.text_run.clone(),
+        })
                        })
                    }
                }
            }
        }
    }
    /// A helper method that uses the breaking strategy described by `slice_iterator` (at present,
@ -2617,11 +2612,11 @@ impl Fragment {
        match self.specific {
            SpecificFragmentInfo::InlineBlock(ref info) => {
                let block_flow = info.flow_ref.as_block();
-                overflow.union(&flow::base(block_flow).overflow);
+                overflow.union(&block_flow.base().overflow);
            }
            SpecificFragmentInfo::InlineAbsolute(ref info) => {
                let block_flow = info.flow_ref.as_block();
-                overflow.union(&flow::base(block_flow).overflow);
+                overflow.union(&block_flow.base().overflow);
            }
            _ => (),
        }
--- a/components/layout/generated_content.rs
+++ b/components/layout/generated_content.rs
@ -9,7 +9,7 @@
 //! as possible.
 use context::{LayoutContext, with_thread_local_font_context};
-use flow::{self, Flow, FlowFlags, ImmutableFlowUtils};
+use flow::{Flow, FlowFlags, GetBaseFlow, ImmutableFlowUtils};
 use fragment::{Fragment, GeneratedContentInfo, SpecificFragmentInfo, UnscannedTextFragmentInfo};
 use gfx::display_list::OpaqueNode;
 use script_layout_interface::wrapper_traits::PseudoElementType;
@ -132,8 +132,8 @@ impl<'a> InorderFlowTraversal for ResolveGeneratedContent<'a> {
    #[inline]
    fn should_process_subtree(&mut self, flow: &mut Flow) -> bool {
-        flow::base(flow).restyle_damage.intersects(ServoRestyleDamage::RESOLVE_GENERATED_CONTENT) ||
+        flow.base().restyle_damage.intersects(ServoRestyleDamage::RESOLVE_GENERATED_CONTENT) ||
-            flow::base(flow).flags.intersects(FlowFlags::AFFECTS_COUNTERS | FlowFlags::HAS_COUNTER_AFFECTING_CHILDREN)
+            flow.base().flags.intersects(FlowFlags::AFFECTS_COUNTERS | FlowFlags::HAS_COUNTER_AFFECTING_CHILDREN)
    }
 }
@ -311,9 +311,9 @@ impl<'a, 'b> ResolveGeneratedContentFragmentMutator<'a, 'b> {
                &quotes.0[self.traversal.quote as usize]
            };
        if close {
-            close_quote.clone()
+            close_quote.to_string()
        } else {
-            open_quote.clone()
+            open_quote.to_string()
        }
    }
 }
--- a/components/layout/incremental.rs
+++ b/components/layout/incremental.rs
@ -2,7 +2,7 @@
 * License, v. 2.0. If a copy of the MPL was not distributed with this
 * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
-use flow::{self, FlowFlags, Flow};
+use flow::{FlowFlags, Flow, GetBaseFlow};
 use style::computed_values::float::T as Float;
 use style::selector_parser::RestyleDamage;
 use style::servo::restyle_damage::ServoRestyleDamage;
@ -30,20 +30,20 @@ pub trait LayoutDamageComputation {
 impl<'a> LayoutDamageComputation for &'a mut Flow {
    fn compute_layout_damage(self) -> SpecialRestyleDamage {
        let mut special_damage = SpecialRestyleDamage::empty();
-        let is_absolutely_positioned = flow::base(self).flags.contains(FlowFlags::IS_ABSOLUTELY_POSITIONED);
+        let is_absolutely_positioned = self.base().flags.contains(FlowFlags::IS_ABSOLUTELY_POSITIONED);
        // In addition to damage, we use this phase to compute whether nodes affect CSS counters.
        let mut has_counter_affecting_children = false;
        {
-            let self_base = flow::mut_base(self);
+            let self_base = self.mut_base();
            // Take a snapshot of the parent damage before updating it with damage from children.
            let parent_damage = self_base.restyle_damage;
            for kid in self_base.children.iter_mut() {
                let child_is_absolutely_positioned =
-                    flow::base(kid).flags.contains(FlowFlags::IS_ABSOLUTELY_POSITIONED);
+                    kid.base().flags.contains(FlowFlags::IS_ABSOLUTELY_POSITIONED);
-                flow::mut_base(kid).restyle_damage.insert(
+                kid.mut_base().restyle_damage.insert(
                    parent_damage.damage_for_child(is_absolutely_positioned,
                                                   child_is_absolutely_positioned));
                {
@ -51,16 +51,16 @@ impl<'a> LayoutDamageComputation for &'a mut Flow {
                    special_damage.insert(kid.compute_layout_damage());
                }
                self_base.restyle_damage
-                         .insert(flow::base(kid).restyle_damage.damage_for_parent(
+                         .insert(kid.base().restyle_damage.damage_for_parent(
                                 child_is_absolutely_positioned));
                has_counter_affecting_children = has_counter_affecting_children ||
-                    flow::base(kid).flags.intersects(FlowFlags::AFFECTS_COUNTERS |
+                    kid.base().flags.intersects(FlowFlags::AFFECTS_COUNTERS |
                                                     FlowFlags::HAS_COUNTER_AFFECTING_CHILDREN);
            }
        }
-        let self_base = flow::mut_base(self);
+        let self_base = self.mut_base();
        if self_base.flags.float_kind() != Float::None &&
                self_base.restyle_damage.intersects(ServoRestyleDamage::REFLOW) {
            special_damage.insert(SpecialRestyleDamage::REFLOW_ENTIRE_DOCUMENT);
@ -76,7 +76,7 @@ impl<'a> LayoutDamageComputation for &'a mut Flow {
    }
    fn reflow_entire_document(self) {
-        let self_base = flow::mut_base(self);
+        let self_base = self.mut_base();
        self_base.restyle_damage.insert(RestyleDamage::rebuild_and_reflow());
        self_base.restyle_damage.remove(ServoRestyleDamage::RECONSTRUCT_FLOW);
        for kid in self_base.children.iter_mut() {
--- a/components/layout/inline.rs
+++ b/components/layout/inline.rs
@ -12,8 +12,8 @@ use display_list_builder::{DisplayListBuildState, InlineFlowDisplayListBuilding}
 use display_list_builder::StackingContextCollectionState;
 use euclid::{Point2D, Size2D};
 use floats::{FloatKind, Floats, PlacementInfo};
-use flow::{self, BaseFlow, Flow, FlowClass, ForceNonfloatedFlag};
+use flow::{BaseFlow, Flow, FlowClass, ForceNonfloatedFlag};
-use flow::{FlowFlags, EarlyAbsolutePositionInfo, OpaqueFlow};
+use flow::{FlowFlags, EarlyAbsolutePositionInfo, GetBaseFlow, OpaqueFlow};
 use flow_ref::FlowRef;
 use fragment::{CoordinateSystem, Fragment, FragmentBorderBoxIterator, Overflow};
 use fragment::FragmentFlags;
@ -1315,7 +1315,7 @@ impl Flow for InlineFlow {
        let writing_mode = self.base.writing_mode;
        for kid in self.base.child_iter_mut() {
-            flow::mut_base(kid).floats = Floats::new(writing_mode);
+            kid.mut_base().floats = Floats::new(writing_mode);
        }
        self.base.flags.remove(FlowFlags::CONTAINS_TEXT_OR_REPLACED_FRAGMENTS);
@ -1423,7 +1423,7 @@ impl Flow for InlineFlow {
        // sizes down to them.
        let block_container_explicit_block_size = self.base.block_container_explicit_block_size;
        for kid in self.base.child_iter_mut() {
-            let kid_base = flow::mut_base(kid);
+            let kid_base = kid.mut_base();
            kid_base.block_container_inline_size = inline_size;
            kid_base.block_container_writing_mode = container_mode;
@ -1524,14 +1524,14 @@ impl Flow for InlineFlow {
            match f.specific {
                SpecificFragmentInfo::InlineBlock(ref mut info) => {
                    let block = FlowRef::deref_mut(&mut info.flow_ref);
-                    flow::mut_base(block).early_absolute_position_info = EarlyAbsolutePositionInfo {
+                    block.mut_base().early_absolute_position_info = EarlyAbsolutePositionInfo {
                        relative_containing_block_size: containing_block_size,
                        relative_containing_block_mode: writing_mode,
                    };
                }
                SpecificFragmentInfo::InlineAbsolute(ref mut info) => {
                    let block = FlowRef::deref_mut(&mut info.flow_ref);
-                    flow::mut_base(block).early_absolute_position_info = EarlyAbsolutePositionInfo {
+                    block.mut_base().early_absolute_position_info = EarlyAbsolutePositionInfo {
                        relative_containing_block_size: containing_block_size,
                        relative_containing_block_mode: writing_mode,
                    };
@ -1757,7 +1757,7 @@ impl fmt::Debug for InlineFlow {
               "{:?}({:x}) {:?}",
               self.class(),
               self.base.debug_id(),
-               flow::base(self))
+               self.base())
    }
 }
--- a/components/layout/layout_debug.rs
+++ b/components/layout/layout_debug.rs
@ -5,7 +5,7 @@
 //! Supports writing a trace file created during each layout scope
 //! that can be viewed by an external tool to make layout debugging easier.
-use flow;
+use flow::GetBaseFlow;
 use flow_ref::FlowRef;
 use serde_json::{to_string, to_value, Value};
 use std::borrow::ToOwned;
@ -63,7 +63,7 @@ impl Scope {
    pub fn new(name: String) -> Scope {
        STATE_KEY.with(|ref r| {
            if let Some(ref mut state) = *r.borrow_mut() {
-                let flow_trace = to_value(&flow::base(&*state.flow_root)).unwrap();
+                let flow_trace = to_value(&state.flow_root.base()).unwrap();
                let data = Box::new(ScopeData::new(name.clone(), flow_trace));
                state.scope_stack.push(data);
            }
@ -78,7 +78,7 @@ impl Drop for Scope {
        STATE_KEY.with(|ref r| {
            if let Some(ref mut state) = *r.borrow_mut() {
                let mut current_scope = state.scope_stack.pop().unwrap();
-                current_scope.post = to_value(&flow::base(&*state.flow_root)).unwrap();
+                current_scope.post = to_value(&state.flow_root.base()).unwrap();
                let previous_scope = state.scope_stack.last_mut().unwrap();
                previous_scope.children.push(current_scope);
            }
@ -100,7 +100,7 @@ pub fn begin_trace(flow_root: FlowRef) {
    assert!(STATE_KEY.with(|ref r| r.borrow().is_none()));
    STATE_KEY.with(|ref r| {
-        let flow_trace = to_value(&flow::base(&*flow_root)).unwrap();
+        let flow_trace = to_value(&flow_root.base()).unwrap();
        let state = State {
            scope_stack: vec![Box::new(ScopeData::new("root".to_owned(), flow_trace))],
            flow_root: flow_root.clone(),
@ -116,7 +116,7 @@ pub fn end_trace(generation: u32) {
    let mut thread_state = STATE_KEY.with(|ref r| r.borrow_mut().take().unwrap());
    assert!(thread_state.scope_stack.len() == 1);
    let mut root_scope = thread_state.scope_stack.pop().unwrap();
-    root_scope.post = to_value(&flow::base(&*thread_state.flow_root)).unwrap();
+    root_scope.post = to_value(&thread_state.flow_root.base()).unwrap();
    let result = to_string(&root_scope).unwrap();
    let mut file = File::create(format!("layout_trace-{}.json", generation)).unwrap();
--- a/components/layout/multicol.rs
+++ b/components/layout/multicol.rs
@ -13,7 +13,7 @@ use context::LayoutContext;
 use display_list_builder::{DisplayListBuildState, StackingContextCollectionState};
 use euclid::{Point2D, Vector2D};
 use floats::FloatKind;
-use flow::{Flow, FlowClass, OpaqueFlow, mut_base, FragmentationContext};
+use flow::{Flow, FlowClass, OpaqueFlow, FragmentationContext, GetBaseFlow};
 use fragment::{Fragment, FragmentBorderBoxIterator, Overflow};
 use gfx_traits::print_tree::PrintTree;
 use std::cmp::{min, max};
@ -180,7 +180,7 @@ impl Flow for MulticolFlow {
        let pitch = LogicalSize::new(self.block_flow.base.writing_mode, self.column_pitch, Au(0));
        let pitch = pitch.to_physical(self.block_flow.base.writing_mode);
        for (i, child) in self.block_flow.base.children.iter_mut().enumerate() {
-            let point = &mut mut_base(child).stacking_relative_position;
+            let point = &mut child.mut_base().stacking_relative_position;
            *point = *point + Vector2D::new(pitch.width * i as i32, pitch.height * i as i32);
        }
    }
--- a/components/layout/parallel.rs
+++ b/components/layout/parallel.rs
@ -10,7 +10,7 @@
 use block::BlockFlow;
 use context::LayoutContext;
-use flow::{self, Flow};
+use flow::{Flow, GetBaseFlow};
 use flow_ref::FlowRef;
 use profile_traits::time::{self, TimerMetadata, profile};
 use rayon;
@ -84,7 +84,7 @@ fn bottom_up_flow(mut unsafe_flow: UnsafeFlow,
        }
-        let base = flow::mut_base(flow);
+        let base = flow.mut_base();
        // Reset the count of children for the next layout traversal.
        base.parallel.children_count.store(base.children.len() as isize,
@ -103,7 +103,7 @@ fn bottom_up_flow(mut unsafe_flow: UnsafeFlow,
        let parent: &mut Flow = unsafe {
            &mut *(unsafe_parent.0 as *mut Flow)
        };
-        let parent_base = flow::mut_base(parent);
+        let parent_base = parent.mut_base();
        if parent_base.parallel.children_count.fetch_sub(1, Ordering::Relaxed) == 1 {
            // We were the last child of our parent. Reflow our parent.
            unsafe_flow = unsafe_parent
@ -127,7 +127,7 @@ fn top_down_flow<'scope>(unsafe_flows: &[UnsafeFlow],
        unsafe {
            // Get a real flow.
            let flow: &mut Flow = mem::transmute(*unsafe_flow);
-            flow::mut_base(flow).thread_id =
+            flow.mut_base().thread_id =
                pool.current_thread_index().unwrap() as u8;
            if assign_isize_traversal.should_process(flow) {
@ -136,7 +136,7 @@ fn top_down_flow<'scope>(unsafe_flows: &[UnsafeFlow],
            }
            // Possibly enqueue the children.
-            for kid in flow::child_iter_mut(flow) {
+            for kid in flow.mut_base().child_iter_mut() {
                had_children = true;
                discovered_child_flows.push(UnsafeFlow(kid));
            }
--- a/components/layout/query.rs
+++ b/components/layout/query.rs
@ -8,7 +8,7 @@ use app_units::Au;
 use construct::ConstructionResult;
 use context::LayoutContext;
 use euclid::{Point2D, Vector2D, Rect, Size2D};
-use flow::{self, Flow};
+use flow::{Flow, GetBaseFlow};
 use fragment::{Fragment, FragmentBorderBoxIterator, SpecificFragmentInfo};
 use gfx::display_list::{DisplayList, OpaqueNode, ScrollOffsetMap};
 use inline::InlineFragmentNodeFlags;
@ -774,7 +774,7 @@ where
        let position = maybe_data.map_or(Point2D::zero(), |data| {
            match (*data).flow_construction_result {
                ConstructionResult::Flow(ref flow_ref, _) =>
-                    flow::base(flow_ref.deref()).stacking_relative_position.to_point(),
+                    flow_ref.deref().base().stacking_relative_position.to_point(),
                // TODO(dzbarsky) search parents until we find node with a flow ref.
                // https://github.com/servo/servo/issues/8307
                _ => Point2D::zero()
--- a/components/layout/sequential.rs
+++ b/components/layout/sequential.rs
@ -9,7 +9,7 @@ use context::LayoutContext;
 use display_list_builder::{DisplayListBuildState, StackingContextCollectionState};
 use euclid::{Point2D, Vector2D};
 use floats::SpeculatedFloatPlacement;
-use flow::{self, Flow, ImmutableFlowUtils, FlowFlags};
+use flow::{Flow, ImmutableFlowUtils, FlowFlags, GetBaseFlow};
 use fragment::{FragmentBorderBoxIterator, CoordinateSystem};
 use generated_content::ResolveGeneratedContent;
 use incremental::RelayoutMode;
@ -31,7 +31,7 @@ pub fn reflow(root: &mut Flow, layout_context: &LayoutContext, relayout_mode: Re
        // Force reflow children during this traversal. This is needed when we failed
        // the float speculation of a block formatting context and need to fix it.
        if relayout_mode == RelayoutMode::Force {
-            flow::mut_base(flow)
+            flow.mut_base()
                .restyle_damage
                .insert(ServoRestyleDamage::REFLOW_OUT_OF_FLOW | ServoRestyleDamage::REFLOW);
        }
@ -40,7 +40,7 @@ pub fn reflow(root: &mut Flow, layout_context: &LayoutContext, relayout_mode: Re
            assign_inline_sizes.process(flow);
        }
-        for kid in flow::child_iter_mut(flow) {
+        for kid in flow.mut_base().child_iter_mut() {
            doit(kid, assign_inline_sizes, assign_block_sizes, relayout_mode);
        }
@ -87,11 +87,11 @@ pub fn iterate_through_flow_tree_fragment_border_boxes(root: &mut Flow, iterator
            stacking_context_position: &Point2D<Au>) {
        flow.iterate_through_fragment_border_boxes(iterator, level, stacking_context_position);
-        for kid in flow::mut_base(flow).child_iter_mut() {
+        for kid in flow.mut_base().child_iter_mut() {
            let mut stacking_context_position = *stacking_context_position;
            if kid.is_block_flow() && kid.as_block().fragment.establishes_stacking_context() {
                stacking_context_position = Point2D::new(kid.as_block().fragment.margin.inline_start, Au(0)) +
-                                            flow::base(kid).stacking_relative_position +
+                                            kid.base().stacking_relative_position +
                                            stacking_context_position.to_vector();
                let relative_position = kid.as_block()
                    .stacking_relative_border_box(CoordinateSystem::Own);
@ -112,17 +112,17 @@ pub fn iterate_through_flow_tree_fragment_border_boxes(root: &mut Flow, iterator
 }
 pub fn store_overflow(layout_context: &LayoutContext, flow: &mut Flow) {
-    if !flow::base(flow).restyle_damage.contains(ServoRestyleDamage::STORE_OVERFLOW) {
+    if !flow.base().restyle_damage.contains(ServoRestyleDamage::STORE_OVERFLOW) {
        return;
    }
-    for kid in flow::mut_base(flow).child_iter_mut() {
+    for kid in flow.mut_base().child_iter_mut() {
        store_overflow(layout_context, kid);
    }
    flow.store_overflow(layout_context);
-    flow::mut_base(flow)
+    flow.mut_base()
        .restyle_damage
        .remove(ServoRestyleDamage::STORE_OVERFLOW);
 }
@ -131,22 +131,22 @@ pub fn store_overflow(layout_context: &LayoutContext, flow: &mut Flow) {
 /// given flow. This is needed to speculatively calculate the inline sizes of block formatting
 /// contexts. The speculation typically succeeds, but if it doesn't we have to lay it out again.
 pub fn guess_float_placement(flow: &mut Flow) {
-    if !flow::base(flow).restyle_damage.intersects(ServoRestyleDamage::REFLOW) {
+    if !flow.base().restyle_damage.intersects(ServoRestyleDamage::REFLOW) {
        return;
    }
    let mut floats_in = SpeculatedFloatPlacement::compute_floats_in_for_first_child(flow);
-    for kid in flow::mut_base(flow).child_iter_mut() {
+    for kid in flow.mut_base().child_iter_mut() {
-        if flow::base(kid).flags.contains(FlowFlags::IS_ABSOLUTELY_POSITIONED) {
+        if kid.base().flags.contains(FlowFlags::IS_ABSOLUTELY_POSITIONED) {
            // Do not propagate floats in or out, but do propogate between kids.
            guess_float_placement(kid);
        } else {
            floats_in.compute_floats_in(kid);
-            flow::mut_base(kid).speculated_float_placement_in = floats_in;
+            kid.mut_base().speculated_float_placement_in = floats_in;
            guess_float_placement(kid);
-            floats_in = flow::base(kid).speculated_float_placement_out;
+            floats_in = kid.base().speculated_float_placement_out;
        }
    }
    floats_in.compute_floats_out(flow);
-    flow::mut_base(flow).speculated_float_placement_out = floats_in
+    flow.mut_base().speculated_float_placement_out = floats_in
 }
--- a/components/layout/table.rs
+++ b/components/layout/table.rs
@ -13,8 +13,7 @@ use context::LayoutContext;
 use display_list_builder::{BlockFlowDisplayListBuilding, BorderPaintingMode};
 use display_list_builder::{DisplayListBuildState, StackingContextCollectionFlags, StackingContextCollectionState};
 use euclid::Point2D;
-use flow;
+use flow::{BaseFlow, EarlyAbsolutePositionInfo, Flow, FlowClass, ImmutableFlowUtils, GetBaseFlow, OpaqueFlow};
 use flow::{BaseFlow, EarlyAbsolutePositionInfo, Flow, FlowClass, ImmutableFlowUtils, OpaqueFlow};
 use flow_list::MutFlowListIterator;
 use fragment::{Fragment, FragmentBorderBoxIterator, Overflow};
 use gfx_traits::print_tree::PrintTree;
@ -752,12 +751,12 @@ impl TableLikeFlow for BlockFlow {
                }
                // At this point, `current_block_offset` is at the border edge of the child.
-                flow::mut_base(kid).position.start.b = current_block_offset;
+                kid.mut_base().position.start.b = current_block_offset;
                // Move past the child's border box. Do not use the `translate_including_floats`
                // function here because the child has already translated floats past its border
                // box.
-                let kid_base = flow::mut_base(kid);
+                let kid_base = kid.mut_base();
                current_block_offset = current_block_offset + kid_base.position.size.block;
            }
@ -796,7 +795,7 @@ impl TableLikeFlow for BlockFlow {
            // Write in the size of the relative containing block for children. (This information
            // is also needed to handle RTL.)
            for kid in self.base.child_iter_mut() {
-                flow::mut_base(kid).early_absolute_position_info = EarlyAbsolutePositionInfo {
+                kid.mut_base().early_absolute_position_info = EarlyAbsolutePositionInfo {
                    relative_containing_block_size: self.fragment.content_box().size,
                    relative_containing_block_mode: self.fragment.style().writing_mode,
                };
@ -856,7 +855,7 @@ impl<'a> Iterator for TableRowIterator<'a> {
        match self.kids.next() {
            Some(kid) => {
                if kid.is_table_rowgroup() {
-                    self.grandkids = Some(flow::mut_base(kid).child_iter_mut());
+                    self.grandkids = Some(kid.mut_base().child_iter_mut());
                    self.next()
                } else if kid.is_table_row() {
                    Some(kid.as_mut_table_row())
--- a/components/layout/table_cell.rs
+++ b/components/layout/table_cell.rs
@ -13,7 +13,7 @@ use display_list_builder::{BlockFlowDisplayListBuilding, BorderPaintingMode};
 use display_list_builder::{DisplayListBuildState, StackingContextCollectionFlags};
 use display_list_builder::StackingContextCollectionState;
 use euclid::{Point2D, Rect, SideOffsets2D, Size2D};
-use flow::{self, Flow, FlowClass, FlowFlags, OpaqueFlow};
+use flow::{Flow, FlowClass, FlowFlags, GetBaseFlow, OpaqueFlow};
 use fragment::{Fragment, FragmentBorderBoxIterator, Overflow};
 use gfx_traits::print_tree::PrintTree;
 use layout_debug;
@ -101,8 +101,8 @@ impl TableCellFlow {
        // Note to the reader: this code has been tested with negative margins.
        // We end up with a "end" that's before the "start," but the math still works out.
        let mut extents = None;
-        for kid in flow::base(self).children.iter() {
+        for kid in self.base().children.iter() {
-            let kid_base = flow::base(kid);
+            let kid_base = kid.base();
            if kid_base.flags.contains(FlowFlags::IS_ABSOLUTELY_POSITIONED) {
                continue
            }
@ -128,7 +128,7 @@ impl TableCellFlow {
        };
        let kids_size = last_end - first_start;
-        let self_size = flow::base(self).position.size.block -
+        let self_size = self.base().position.size.block -
            self.block_flow.fragment.border_padding.block_start_end();
        let kids_self_gap = self_size - kids_size;
@ -143,8 +143,8 @@ impl TableCellFlow {
            return
        }
-        for kid in flow::mut_base(self).children.iter_mut() {
+        for kid in self.mut_base().children.iter_mut() {
-            let kid_base = flow::mut_base(kid);
+            let kid_base = kid.mut_base();
            if !kid_base.flags.contains(FlowFlags::IS_ABSOLUTELY_POSITIONED) {
                kid_base.position.start.b += offset
            }
--- a/components/layout/table_row.rs
+++ b/components/layout/table_row.rs
@ -13,7 +13,7 @@ use display_list_builder::{BlockFlowDisplayListBuilding, BorderPaintingMode};
 use display_list_builder::{DisplayListBuildState, StackingContextCollectionFlags};
 use display_list_builder::StackingContextCollectionState;
 use euclid::Point2D;
-use flow::{self, EarlyAbsolutePositionInfo, Flow, FlowClass, ImmutableFlowUtils, OpaqueFlow};
+use flow::{EarlyAbsolutePositionInfo, Flow, FlowClass, ImmutableFlowUtils, GetBaseFlow, OpaqueFlow};
 use flow_list::MutFlowListIterator;
 use fragment::{Fragment, FragmentBorderBoxIterator, Overflow};
 use gfx_traits::print_tree::PrintTree;
@ -126,7 +126,7 @@ impl TableRowFlow {
                - self.block_flow.fragment.margin;
            for kid in self.block_flow.base.child_iter_mut() {
                kid.place_float_if_applicable();
-                if !flow::base(kid).flags.is_float() {
+                if !kid.base().flags.is_float() {
                    kid.assign_block_size_for_inorder_child_if_necessary(layout_context,
                                                                         thread_id,
                                                                         content_box);
@ -143,7 +143,7 @@ impl TableRowFlow {
                            child_specified_block_size +
                            child_fragment.border_padding.block_start_end());
                }
-                let child_node = flow::mut_base(kid);
+                let child_node = kid.mut_base();
                child_node.position.start.b = Au(0);
                max_block_size = max(max_block_size, child_node.position.size.block);
            }
@ -301,7 +301,7 @@ impl Flow for TableRowFlow {
                // Collect minimum and preferred inline-sizes of the cell for automatic table layout
                // calculation.
-                let child_base = flow::mut_base(kid);
+                let child_base = kid.mut_base();
                let child_column_inline_size = ColumnIntrinsicInlineSize {
                    minimum_length: match child_specified_inline_size {
                        LengthOrPercentageOrAuto::Auto |
--- a/components/layout/traversal.rs
+++ b/components/layout/traversal.rs
@ -7,7 +7,7 @@
 use construct::FlowConstructor;
 use context::LayoutContext;
 use display_list_builder::DisplayListBuildState;
-use flow::{self, FlowFlags, Flow, ImmutableFlowUtils};
+use flow::{FlowFlags, Flow, GetBaseFlow, ImmutableFlowUtils};
 use script_layout_interface::wrapper_traits::{LayoutNode, ThreadSafeLayoutNode};
 use servo_config::opts;
 use style::context::{SharedStyleContext, StyleContext};
@ -110,7 +110,7 @@ pub trait PreorderFlowTraversal {
        if self.should_process(flow) {
            self.process(flow);
        }
-        for kid in flow::child_iter_mut(flow) {
+        for kid in flow.mut_base().child_iter_mut() {
            self.traverse(kid);
        }
    }
@ -125,7 +125,7 @@ pub trait PreorderFlowTraversal {
        if self.should_process(flow) {
            self.process(flow);
        }
-        for descendant_link in flow::mut_base(flow).abs_descendants.iter() {
+        for descendant_link in flow.mut_base().abs_descendants.iter() {
            self.traverse_absolute_flows(descendant_link)
        }
    }
@ -145,7 +145,7 @@ pub trait PostorderFlowTraversal {
    /// Traverses the tree in postorder.
    fn traverse(&self, flow: &mut Flow) {
-        for kid in flow::child_iter_mut(flow) {
+        for kid in flow.mut_base().child_iter_mut() {
            self.traverse(kid);
        }
        if self.should_process(flow) {
@ -171,7 +171,7 @@ pub trait InorderFlowTraversal {
            return;
        }
        self.process(flow, level);
-        for kid in flow::child_iter_mut(flow) {
+        for kid in flow.mut_base().child_iter_mut() {
            self.traverse(kid, level + 1);
        }
    }
@ -226,12 +226,12 @@ impl<'a> PostorderFlowTraversal for BubbleISizes<'a> {
    #[inline]
    fn process(&self, flow: &mut Flow) {
        flow.bubble_inline_sizes();
-        flow::mut_base(flow).restyle_damage.remove(ServoRestyleDamage::BUBBLE_ISIZES);
+        flow.mut_base().restyle_damage.remove(ServoRestyleDamage::BUBBLE_ISIZES);
    }
    #[inline]
    fn should_process(&self, flow: &mut Flow) -> bool {
-        flow::base(flow).restyle_damage.contains(ServoRestyleDamage::BUBBLE_ISIZES)
+        flow.base().restyle_damage.contains(ServoRestyleDamage::BUBBLE_ISIZES)
    }
 }
@ -249,7 +249,7 @@ impl<'a> PreorderFlowTraversal for AssignISizes<'a> {
    #[inline]
    fn should_process(&self, flow: &mut Flow) -> bool {
-        flow::base(flow).restyle_damage.intersects(ServoRestyleDamage::REFLOW_OUT_OF_FLOW | ServoRestyleDamage::REFLOW)
+        flow.base().restyle_damage.intersects(ServoRestyleDamage::REFLOW_OUT_OF_FLOW | ServoRestyleDamage::REFLOW)
    }
 }
@ -278,7 +278,7 @@ impl<'a> PostorderFlowTraversal for AssignBSizes<'a> {
    #[inline]
    fn should_process(&self, flow: &mut Flow) -> bool {
-        let base = flow::base(flow);
+        let base = flow.base();
        base.restyle_damage.intersects(ServoRestyleDamage::REFLOW_OUT_OF_FLOW | ServoRestyleDamage::REFLOW) &&
        // The fragmentation countainer is responsible for calling Flow::fragment recursively
        !base.flags.contains(FlowFlags::CAN_BE_FRAGMENTED)
@ -292,13 +292,13 @@ pub struct ComputeStackingRelativePositions<'a> {
 impl<'a> PreorderFlowTraversal for ComputeStackingRelativePositions<'a> {
    #[inline]
    fn should_process_subtree(&self, flow: &mut Flow) -> bool {
-        flow::base(flow).restyle_damage.contains(ServoRestyleDamage::REPOSITION)
+        flow.base().restyle_damage.contains(ServoRestyleDamage::REPOSITION)
    }
    #[inline]
    fn process(&self, flow: &mut Flow) {
        flow.compute_stacking_relative_position(self.layout_context);
-        flow::mut_base(flow).restyle_damage.remove(ServoRestyleDamage::REPOSITION)
+        flow.mut_base().restyle_damage.remove(ServoRestyleDamage::REPOSITION)
    }
 }
@ -310,15 +310,15 @@ impl<'a> BuildDisplayList<'a> {
    #[inline]
    pub fn traverse(&mut self, flow: &mut Flow) {
        let parent_stacking_context_id = self.state.current_stacking_context_id;
-        self.state.current_stacking_context_id = flow::base(flow).stacking_context_id;
+        self.state.current_stacking_context_id = flow.base().stacking_context_id;
        let parent_clipping_and_scrolling = self.state.current_clipping_and_scrolling;
        self.state.current_clipping_and_scrolling = flow.clipping_and_scrolling();
        flow.build_display_list(&mut self.state);
-        flow::mut_base(flow).restyle_damage.remove(ServoRestyleDamage::REPAINT);
+        flow.mut_base().restyle_damage.remove(ServoRestyleDamage::REPAINT);
-        for kid in flow::child_iter_mut(flow) {
+        for kid in flow.mut_base().child_iter_mut() {
            self.traverse(kid);
        }
--- a/components/layout/webrender_helpers.rs
+++ b/components/layout/webrender_helpers.rs
@ -428,7 +428,6 @@ impl WebRenderDisplayItemConverter for DisplayItem {
                builder.push_border(&self.prim_info(), widths, details);
            }
            DisplayItem::Gradient(ref item) => {
                let rect = item.base.bounds;
                let start_point = item.gradient.start_point.to_pointf();
                let end_point = item.gradient.end_point.to_pointf();
                let extend_mode = if item.gradient.repeating {
@ -442,11 +441,10 @@ impl WebRenderDisplayItemConverter for DisplayItem {
                                                       extend_mode);
                builder.push_gradient(&self.prim_info(),
                                      gradient,
-                                      rect.size.to_sizef(),
+                                      item.tile.to_sizef(),
                                      webrender_api::LayoutSize::zero());
            }
            DisplayItem::RadialGradient(ref item) => {
                let rect = item.base.bounds;
                let center = item.gradient.center.to_pointf();
                let radius = item.gradient.radius.to_sizef();
                let extend_mode = if item.gradient.repeating {
@ -460,7 +458,7 @@ impl WebRenderDisplayItemConverter for DisplayItem {
                                                              extend_mode);
                builder.push_radial_gradient(&self.prim_info(),
                                             gradient,
-                                             rect.size.to_sizef(),
+                                             item.tile.to_sizef(),
                                             webrender_api::LayoutSize::zero());
            }
            DisplayItem::Line(ref item) => {
--- a/components/layout_thread/lib.rs
+++ b/components/layout_thread/lib.rs
@ -70,7 +70,7 @@ use layout::context::RegisteredPainter;
 use layout::context::RegisteredPainters;
 use layout::context::malloc_size_of_persistent_local_context;
 use layout::display_list_builder::ToGfxColor;
-use layout::flow::{self, Flow, ImmutableFlowUtils, MutableOwnedFlowUtils};
+use layout::flow::{Flow, GetBaseFlow, ImmutableFlowUtils, MutableOwnedFlowUtils};
 use layout::flow_ref::FlowRef;
 use layout::incremental::{LayoutDamageComputation, RelayoutMode, SpecialRestyleDamage};
 use layout::layout_debug;
@ -956,22 +956,22 @@ impl LayoutThread {
                                              layout_root: &mut Flow,
                                              layout_context: &mut LayoutContext,
                                              rw_data: &mut LayoutThreadData) {
-        let writing_mode = flow::base(layout_root).writing_mode;
+        let writing_mode = layout_root.base().writing_mode;
        let (metadata, sender) = (self.profiler_metadata(), self.time_profiler_chan.clone());
        profile(time::ProfilerCategory::LayoutDispListBuild,
                metadata.clone(),
                sender.clone(),
                || {
-            flow::mut_base(layout_root).stacking_relative_position =
+            layout_root.mut_base().stacking_relative_position =
                LogicalPoint::zero(writing_mode).to_physical(writing_mode,
                                                             self.viewport_size).to_vector();
-            flow::mut_base(layout_root).clip = data.page_clip_rect;
+            layout_root.mut_base().clip = data.page_clip_rect;
            let traversal = ComputeStackingRelativePositions { layout_context: layout_context };
            traversal.traverse(layout_root);
-            if flow::base(layout_root).restyle_damage.contains(ServoRestyleDamage::REPAINT) ||
+            if layout_root.base().restyle_damage.contains(ServoRestyleDamage::REPAINT) ||
                    rw_data.display_list.is_none() {
                if reflow_goal.needs_display_list() {
                    let mut build_state =
@ -980,7 +980,7 @@ impl LayoutThread {
                    debug!("Done building display list.");
                    let root_size = {
-                        let root_flow = flow::base(layout_root);
+                        let root_flow = layout_root.base();
                        if self.stylist.viewport_constraints().is_some() {
                            root_flow.position.size.to_physical(root_flow.writing_mode)
                        } else {
@ -1564,7 +1564,7 @@ impl LayoutThread {
        // Perform the primary layout passes over the flow tree to compute the locations of all
        // the boxes.
-        if flow::base(&**root_flow).restyle_damage.intersects(ServoRestyleDamage::REFLOW |
+        if root_flow.base().restyle_damage.intersects(ServoRestyleDamage::REFLOW |
                                                              ServoRestyleDamage::REFLOW_OUT_OF_FLOW) {
            profile(time::ProfilerCategory::LayoutMain,
                    self.profiler_metadata(),
@ -1630,12 +1630,12 @@ impl LayoutThread {
    fn reflow_all_nodes(flow: &mut Flow) {
        debug!("reflowing all nodes!");
-        flow::mut_base(flow)
+        flow.mut_base()
            .restyle_damage
            .insert(ServoRestyleDamage::REPAINT | ServoRestyleDamage::STORE_OVERFLOW |
                    ServoRestyleDamage::REFLOW | ServoRestyleDamage::REPOSITION);
-        for child in flow::child_iter_mut(flow) {
+        for child in flow.mut_base().child_iter_mut() {
            LayoutThread::reflow_all_nodes(child);
        }
    }
--- a/components/net/http_cache.rs
+++ b/components/net/http_cache.rs
@ -479,10 +479,7 @@ impl HttpCache {
            return None;
        }
        let entry_key = CacheKey::new(request.clone());
-        let resources = match self.entries.get(&entry_key) {
+        let resources = self.entries.get(&entry_key)?.clone();
            Some(ref resources) => resources.clone(),
            None => return None,
        };
        let mut candidates = vec![];
        for cached_resource in resources.iter() {
            let mut can_be_constructed = true;
--- a/components/script/Cargo.toml
+++ b/components/script/Cargo.toml
@ -39,6 +39,7 @@ byteorder = "1.0"
 canvas_traits = {path = "../canvas_traits"}
 caseless = "0.1.0"
 cookie = "0.10"
 chrono = "0.4"
 cssparser = "0.23.0"
 deny_public_fields = {path = "../deny_public_fields"}
 devtools_traits = {path = "../devtools_traits"}
--- a/components/script/document_loader.rs
+++ b/components/script/document_loader.rs
@ -141,6 +141,13 @@ impl DocumentLoader {
        !self.blocking_loads.is_empty()
    }
    pub fn is_only_blocked_by_iframes(&self) -> bool {
        self.blocking_loads.iter().all(|load| match *load {
            LoadType::Subframe(_) => true,
            _ => false
        })
    }
    pub fn inhibit_events(&mut self) {
        self.events_inhibited = true;
    }
--- a/components/script/dom/bindings/str.rs
+++ b/components/script/dom/bindings/str.rs
@ -4,6 +4,8 @@
 //! The `ByteString` struct.
 use chrono::{Datelike, TimeZone};
 use chrono::prelude::{Weekday, Utc};
 use cssparser::CowRcStr;
 use html5ever::{LocalName, Namespace};
 use servo_atoms::Atom;
@ -293,6 +295,13 @@ impl DOMString {
    pub fn is_valid_month_string(&self) -> bool {
        parse_month_string(&*self.0).is_ok()
    }
    /// A valid week string should be like {YYYY}-W{WW}, such as "2017-W52"
    /// YYYY must be four or more digits, WW both must be two digits
    /// https://html.spec.whatwg.org/multipage/#valid-week-string
    pub fn is_valid_week_string(&self) -> bool {
        parse_week_string(&*self.0).is_ok()
    }
 }
 impl Borrow<str> for DOMString {
@ -445,6 +454,48 @@ fn parse_date_string(value: &str) -> Result<(u32, u32, u32), ()> {
    Ok((year_int, month_int, day_int))
 }
 /// https://html.spec.whatwg.org/multipage/#parse-a-week-string
 fn parse_week_string(value: &str) -> Result<(u32, u32), ()> {
    // Step 1, 2, 3
    let mut iterator = value.split('-');
    let year = iterator.next().ok_or(())?;
    // Step 4
    let year_int = year.parse::<u32>().map_err(|_| ())?;
    if year.len() < 4 || year_int == 0 {
        return Err(());
    }
    // Step 5, 6
    let week = iterator.next().ok_or(())?;
    let (week_first, week_last) = week.split_at(1);
    if week_first != "W" {
        return Err(());
    }
    // Step 7
    let week_int = week_last.parse::<u32>().map_err(|_| ())?;
    if week_last.len() != 2 {
        return Err(());
    }
    // Step 8
    let max_week = max_week_in_year(year_int);
    // Step 9
    if week_int < 1 || week_int > max_week {
        return Err(());
    }
    // Step 10
    if iterator.next().is_some() {
        return Err(());
    }
    // Step 11
    Ok((year_int, week_int))
 }
 /// https://html.spec.whatwg.org/multipage/#parse-a-month-component
 fn parse_month_component(value: &str) -> Result<(u32, u32), ()> {
    // Step 3
@ -495,7 +546,7 @@ fn max_day_in_month(year_num: u32, month_num: u32) -> Result<u32, ()> {
        1|3|5|7|8|10|12 => Ok(31),
        4|6|9|11 => Ok(30),
        2 => {
-            if year_num % 400 == 0 || (year_num % 4 == 0 && year_num % 100 != 0) {
+            if is_leap_year(year_num) {
                Ok(29)
            } else {
                Ok(28)
@ -504,3 +555,17 @@ fn max_day_in_month(year_num: u32, month_num: u32) -> Result<u32, ()> {
        _ => Err(())
    }
 }
 // https://html.spec.whatwg.org/multipage/#week-number-of-the-last-day
 fn max_week_in_year(year: u32) -> u32 {
    match Utc.ymd(year as i32, 1, 1).weekday() {
        Weekday::Thu => 53,
        Weekday::Wed if is_leap_year(year) => 53,
        _ => 52
    }
 }
 #[inline]
 fn is_leap_year(year: u32) -> bool {
    year % 400 == 0 || (year % 4 == 0 && year % 100 != 0)
 }
--- a/components/script/dom/canvasrenderingcontext2d.rs
+++ b/components/script/dom/canvasrenderingcontext2d.rs
@ -129,11 +129,10 @@ impl CanvasRenderingContext2D {
                         size: Size2D<i32>)
                         -> CanvasRenderingContext2D {
        debug!("Creating new canvas rendering context.");
-        let (sender, receiver) = ipc::channel().unwrap();
+        let (ipc_renderer, receiver) = ipc::channel::<CanvasMsg>().unwrap();
        let script_to_constellation_chan = global.script_to_constellation_chan();
        debug!("Asking constellation to create new canvas thread.");
-        script_to_constellation_chan.send(ScriptMsg::CreateCanvasPaintThread(size, sender)).unwrap();
+        script_to_constellation_chan.send(ScriptMsg::CreateCanvasPaintThread(size, receiver)).unwrap();
        let ipc_renderer = receiver.recv().unwrap();
        debug!("Done.");
        CanvasRenderingContext2D {
            reflector_: Reflector::new(),
--- a/components/script/dom/document.rs
+++ b/components/script/dom/document.rs
@ -322,6 +322,7 @@ pub struct Document {
    dom_content_loaded_event_start: Cell<u64>,
    dom_content_loaded_event_end: Cell<u64>,
    dom_complete: Cell<u64>,
    top_level_dom_complete: Cell<u64>,
    load_event_start: Cell<u64>,
    load_event_end: Cell<u64>,
    /// <https://html.spec.whatwg.org/multipage/#concept-document-https-state>
@ -1627,6 +1628,12 @@ impl Document {
        // asap_in_order_script_loaded.
        let loader = self.loader.borrow();
        // Servo measures when the top-level content (not iframes) is loaded.
        if (self.top_level_dom_complete.get() == 0) && loader.is_only_blocked_by_iframes() {
            update_with_current_time_ms(&self.top_level_dom_complete);
        }
        if loader.is_blocked() || loader.events_inhibited() {
            // Step 6.
            return;
@ -1951,6 +1958,10 @@ impl Document {
        self.dom_complete.get()
    }
    pub fn get_top_level_dom_complete(&self) -> u64 {
        self.top_level_dom_complete.get()
    }
    pub fn get_load_event_start(&self) -> u64 {
        self.load_event_start.get()
    }
@ -2265,6 +2276,7 @@ impl Document {
            dom_content_loaded_event_start: Cell::new(Default::default()),
            dom_content_loaded_event_end: Cell::new(Default::default()),
            dom_complete: Cell::new(Default::default()),
            top_level_dom_complete: Cell::new(Default::default()),
            load_event_start: Cell::new(Default::default()),
            load_event_end: Cell::new(Default::default()),
            https_state: Cell::new(HttpsState::None),
--- a/components/script/dom/htmlinputelement.rs
+++ b/components/script/dom/htmlinputelement.rs
@ -405,6 +405,18 @@ impl TextControl for HTMLInputElement {
    fn textinput(&self) -> &DomRefCell<TextInput<ScriptToConstellationChan>> {
        &self.textinput
    }
    // https://html.spec.whatwg.org/multipage/#concept-input-apply
    fn selection_api_applies(&self) -> bool {
        match self.input_type() {
            InputType::Text | InputType::Search | InputType::Url
            | InputType::Tel | InputType::Password => {
                true
            },
            _ => false
        }
    }
 }
 impl HTMLInputElementMethods for HTMLInputElement {
@ -676,38 +688,38 @@ impl HTMLInputElementMethods for HTMLInputElement {
    }
    // https://html.spec.whatwg.org/multipage/#dom-textarea/input-selectionstart
-    fn SelectionStart(&self) -> u32 {
+    fn GetSelectionStart(&self) -> Option<u32> {
-        self.dom_selection_start()
+        self.get_dom_selection_start()
    }
    // https://html.spec.whatwg.org/multipage/#dom-textarea/input-selectionstart
-    fn SetSelectionStart(&self, start: u32) {
+    fn SetSelectionStart(&self, start: Option<u32>) -> ErrorResult {
-        self.set_dom_selection_start(start);
+        self.set_dom_selection_start(start)
    }
    // https://html.spec.whatwg.org/multipage/#dom-textarea/input-selectionend
-    fn SelectionEnd(&self) -> u32 {
+    fn GetSelectionEnd(&self) -> Option<u32> {
-        self.dom_selection_end()
+        self.get_dom_selection_end()
    }
    // https://html.spec.whatwg.org/multipage/#dom-textarea/input-selectionend
-    fn SetSelectionEnd(&self, end: u32) {
+    fn SetSelectionEnd(&self, end: Option<u32>) -> ErrorResult {
        self.set_dom_selection_end(end)
    }
    // https://html.spec.whatwg.org/multipage/#dom-textarea/input-selectiondirection
-    fn SelectionDirection(&self) -> DOMString {
+    fn GetSelectionDirection(&self) -> Option<DOMString> {
-        self.dom_selection_direction()
+        self.get_dom_selection_direction()
    }
    // https://html.spec.whatwg.org/multipage/#dom-textarea/input-selectiondirection
-    fn SetSelectionDirection(&self, direction: DOMString) {
+    fn SetSelectionDirection(&self, direction: Option<DOMString>) -> ErrorResult {
-        self.set_dom_selection_direction(direction);
+        self.set_dom_selection_direction(direction)
    }
    // https://html.spec.whatwg.org/multipage/#dom-textarea/input-setselectionrange
-    fn SetSelectionRange(&self, start: u32, end: u32, direction: Option<DOMString>) {
+    fn SetSelectionRange(&self, start: u32, end: u32, direction: Option<DOMString>) -> ErrorResult {
-        self.set_dom_selection_range(start, end, direction);
+        self.set_dom_selection_range(start, end, direction)
    }
    // Select the files based on filepaths passed in,
@ -993,6 +1005,12 @@ impl HTMLInputElement {
                    *textinput.single_line_content_mut() = "".into();
                }
            }
            InputType::Week => {
                let mut textinput = self.textinput.borrow_mut();
                if !textinput.single_line_content().is_valid_week_string() {
                    *textinput.single_line_content_mut() = "".into();
                }
            }
            InputType::Color => {
                let mut textinput = self.textinput.borrow_mut();
--- a/components/script/dom/htmllegendelement.rs
+++ b/components/script/dom/htmllegendelement.rs
@ -75,10 +75,7 @@ impl VirtualMethods for HTMLLegendElement {
 impl HTMLLegendElementMethods for HTMLLegendElement {
    // https://html.spec.whatwg.org/multipage/#dom-legend-form
    fn GetForm(&self) -> Option<DomRoot<HTMLFormElement>> {
-        let parent = match self.upcast::<Node>().GetParentElement() {
+        let parent = self.upcast::<Node>().GetParentElement()?;
            Some(parent) => parent,
            None => return None,
        };
        if parent.is::<HTMLFieldSetElement>() {
            return self.form_owner();
        }
--- a/components/script/dom/htmltextareaelement.rs
+++ b/components/script/dom/htmltextareaelement.rs
@ -8,6 +8,7 @@ use dom::bindings::codegen::Bindings::EventBinding::EventMethods;
 use dom::bindings::codegen::Bindings::HTMLTextAreaElementBinding;
 use dom::bindings::codegen::Bindings::HTMLTextAreaElementBinding::HTMLTextAreaElementMethods;
 use dom::bindings::codegen::Bindings::NodeBinding::NodeMethods;
 use dom::bindings::error::ErrorResult;
 use dom::bindings::inheritance::Castable;
 use dom::bindings::root::{DomRoot, LayoutDom, MutNullableDom};
 use dom::bindings::str::DOMString;
@ -145,6 +146,10 @@ impl TextControl for HTMLTextAreaElement {
    fn textinput(&self) -> &DomRefCell<TextInput<ScriptToConstellationChan>> {
        &self.textinput
    }
    fn selection_api_applies(&self) -> bool {
        true
    }
 }
 impl HTMLTextAreaElementMethods for HTMLTextAreaElement {
@ -260,38 +265,38 @@ impl HTMLTextAreaElementMethods for HTMLTextAreaElement {
    }
    // https://html.spec.whatwg.org/multipage/#dom-textarea/input-selectionstart
-    fn SelectionStart(&self) -> u32 {
+    fn GetSelectionStart(&self) -> Option<u32> {
-        self.dom_selection_start()
+        self.get_dom_selection_start()
    }
    // https://html.spec.whatwg.org/multipage/#dom-textarea/input-selectionstart
-    fn SetSelectionStart(&self, start: u32) {
+    fn SetSelectionStart(&self, start: Option<u32>) -> ErrorResult {
-        self.set_dom_selection_start(start);
+        self.set_dom_selection_start(start)
    }
    // https://html.spec.whatwg.org/multipage/#dom-textarea/input-selectionend
-    fn SelectionEnd(&self) -> u32 {
+    fn GetSelectionEnd(&self) -> Option<u32> {
-        self.dom_selection_end()
+        self.get_dom_selection_end()
    }
    // https://html.spec.whatwg.org/multipage/#dom-textarea/input-selectionend
-    fn SetSelectionEnd(&self, end: u32) {
+    fn SetSelectionEnd(&self, end: Option<u32>) -> ErrorResult {
-        self.set_dom_selection_end(end);
+        self.set_dom_selection_end(end)
    }
    // https://html.spec.whatwg.org/multipage/#dom-textarea/input-selectiondirection
-    fn SelectionDirection(&self) -> DOMString {
+    fn GetSelectionDirection(&self) -> Option<DOMString> {
-        self.dom_selection_direction()
+        self.get_dom_selection_direction()
    }
    // https://html.spec.whatwg.org/multipage/#dom-textarea/input-selectiondirection
-    fn SetSelectionDirection(&self, direction: DOMString) {
+    fn SetSelectionDirection(&self, direction: Option<DOMString>) -> ErrorResult {
-        self.set_dom_selection_direction(direction);
+        self.set_dom_selection_direction(direction)
    }
    // https://html.spec.whatwg.org/multipage/#dom-textarea/input-setselectionrange
-    fn SetSelectionRange(&self, start: u32, end: u32, direction: Option<DOMString>) {
+    fn SetSelectionRange(&self, start: u32, end: u32, direction: Option<DOMString>) -> ErrorResult {
-        self.set_dom_selection_range(start, end, direction);
+        self.set_dom_selection_range(start, end, direction)
    }
 }
--- a/components/script/dom/performancetiming.rs
+++ b/components/script/dom/performancetiming.rs
@ -86,6 +86,12 @@ impl PerformanceTimingMethods for PerformanceTiming {
    fn LoadEventEnd(&self) -> u64 {
        self.document.get_load_event_end()
    }
    // check-tidy: no specs after this line
    // Servo-only timing for when top-level content (not iframes) is complete
    fn TopLevelDomComplete(&self) -> u64 {
        self.document.get_top_level_dom_complete()
    }
 }
--- a/components/script/dom/textcontrol.rs
+++ b/components/script/dom/textcontrol.rs
@ -4,6 +4,7 @@
 use dom::bindings::cell::DomRefCell;
 use dom::bindings::conversions::DerivedFrom;
 use dom::bindings::error::{Error, ErrorResult};
 use dom::bindings::str::DOMString;
 use dom::event::{EventBubbles, EventCancelable};
 use dom::eventtarget::EventTarget;
@ -13,52 +14,108 @@ use textinput::{SelectionDirection, TextInput};
 pub trait TextControl: DerivedFrom<EventTarget> + DerivedFrom<Node> {
    fn textinput(&self) -> &DomRefCell<TextInput<ScriptToConstellationChan>>;
    fn selection_api_applies(&self) -> bool;
    // https://html.spec.whatwg.org/multipage/#dom-textarea/input-selectionstart
-    fn dom_selection_start(&self) -> u32 {
+    fn get_dom_selection_start(&self) -> Option<u32> {
-        self.textinput().borrow().get_selection_start()
+        // Step 1
        if !self.selection_api_applies() {
            return None;
        }
        // Steps 2-3
        Some(self.selection_start())
    }
    // https://html.spec.whatwg.org/multipage/#dom-textarea/input-selectionstart
-    fn set_dom_selection_start(&self, start: u32) {
+    fn set_dom_selection_start(&self, start: Option<u32>) -> ErrorResult {
        // Step 1
        if !self.selection_api_applies() {
            return Err(Error::InvalidState);
        }
        // Step 2
-        let mut end = self.dom_selection_end();
+        let mut end = self.selection_end();
        // Step 3
-        if end < start {
+        if let Some(s) = start {
-            end = start;
+            if end < s {
                end = s;
            }
        }
        // Step 4
-        self.set_selection_range(start, end, self.selection_direction());
+        self.set_selection_range(start, Some(end), Some(self.selection_direction()));
        Ok(())
    }
    // https://html.spec.whatwg.org/multipage/#dom-textarea/input-selectionend
-    fn dom_selection_end(&self) -> u32 {
+    fn get_dom_selection_end(&self) -> Option<u32> {
-        self.textinput().borrow().get_absolute_insertion_point() as u32
+        // Step 1
        if !self.selection_api_applies() {
            return None;
        }
        // Steps 2-3
        Some(self.selection_end())
    }
    // https://html.spec.whatwg.org/multipage/#dom-textarea/input-selectionend
-    fn set_dom_selection_end(&self, end: u32) {
+    fn set_dom_selection_end(&self, end: Option<u32>) -> ErrorResult {
-        self.set_selection_range(self.dom_selection_start(), end, self.selection_direction());
+        // Step 1
        if !self.selection_api_applies() {
            return Err(Error::InvalidState);
        }
        // Step 2
        self.set_selection_range(Some(self.selection_start()), end, Some(self.selection_direction()));
        Ok(())
    }
    // https://html.spec.whatwg.org/multipage/#dom-textarea/input-selectiondirection
-    fn dom_selection_direction(&self) -> DOMString {
+    fn get_dom_selection_direction(&self) -> Option<DOMString> {
-        DOMString::from(self.selection_direction())
+        // Step 1
        if !self.selection_api_applies() {
            return None;
        }
        Some(DOMString::from(self.selection_direction()))
    }
    // https://html.spec.whatwg.org/multipage/#dom-textarea/input-selectiondirection
-    fn set_dom_selection_direction(&self, direction: DOMString) {
+    fn set_dom_selection_direction(&self, direction: Option<DOMString>) -> ErrorResult {
-        self.textinput().borrow_mut().selection_direction = SelectionDirection::from(direction);
+        // Step 1
        if !self.selection_api_applies() {
            return Err(Error::InvalidState);
        }
        // Step 2
        self.set_selection_range(
            Some(self.selection_start()),
            Some(self.selection_end()),
            direction.map(|d| SelectionDirection::from(d))
        );
        Ok(())
    }
    // https://html.spec.whatwg.org/multipage/#dom-textarea/input-setselectionrange
-    fn set_dom_selection_range(&self, start: u32, end: u32, direction: Option<DOMString>) {
+    fn set_dom_selection_range(&self, start: u32, end: u32, direction: Option<DOMString>) -> ErrorResult {
-        // Step 4
+        // Step 1
-        let direction = direction.map_or(SelectionDirection::None, |d| SelectionDirection::from(d));
+        if !self.selection_api_applies() {
            return Err(Error::InvalidState);
        }
-        self.set_selection_range(start, end, direction);
+        // Step 2
        self.set_selection_range(Some(start), Some(end), direction.map(|d| SelectionDirection::from(d)));
        Ok(())
    }
    fn selection_start(&self) -> u32 {
        self.textinput().borrow().get_selection_start()
    }
    fn selection_end(&self) -> u32 {
        self.textinput().borrow().get_absolute_insertion_point() as u32
    }
    fn selection_direction(&self) -> SelectionDirection {
@ -66,12 +123,15 @@ pub trait TextControl: DerivedFrom<EventTarget> + DerivedFrom<Node> {
    }
    // https://html.spec.whatwg.org/multipage/#set-the-selection-range
-    fn set_selection_range(&self, start: u32, end: u32, direction: SelectionDirection) {
+    fn set_selection_range(&self, start: Option<u32>, end: Option<u32>, direction: Option<SelectionDirection>) {
-        // Step 5
+        // Step 1
-        self.textinput().borrow_mut().selection_direction = direction;
+        let start = start.unwrap_or(0);
-        // Step 3
+        // Step 2
-        self.textinput().borrow_mut().set_selection_range(start, end);
+        let end = end.unwrap_or(0);
        // Steps 3-5
        self.textinput().borrow_mut().set_selection_range(start, end, direction.unwrap_or(SelectionDirection::None));
        // Step 6
        let window = window_from_node(self);
--- a/components/script/dom/webidls/HTMLInputElement.webidl
+++ b/components/script/dom/webidls/HTMLInputElement.webidl
@ -90,13 +90,17 @@ interface HTMLInputElement : HTMLElement {
  readonly attribute NodeList labels;
  //void select();
-           attribute unsigned long selectionStart;
+  [SetterThrows]
-           attribute unsigned long selectionEnd;
+           attribute unsigned long? selectionStart;
-           attribute DOMString selectionDirection;
+  [SetterThrows]
           attribute unsigned long? selectionEnd;
  [SetterThrows]
           attribute DOMString? selectionDirection;
  //void setRangeText(DOMString replacement);
  //void setRangeText(DOMString replacement, unsigned long start, unsigned long end,
  //                  optional SelectionMode selectionMode = "preserve");
-  void setSelectionRange(unsigned long start, unsigned long end, optional DOMString direction);
+  [Throws]
           void setSelectionRange(unsigned long start, unsigned long end, optional DOMString direction);
  // also has obsolete members
--- a/components/script/dom/webidls/HTMLTextAreaElement.webidl
+++ b/components/script/dom/webidls/HTMLTextAreaElement.webidl
@ -51,11 +51,15 @@ interface HTMLTextAreaElement : HTMLElement {
  readonly attribute NodeList labels;
  // void select();
-           attribute unsigned long selectionStart;
+  [SetterThrows]
-           attribute unsigned long selectionEnd;
+           attribute unsigned long? selectionStart;
-           attribute DOMString selectionDirection;
+  [SetterThrows]
           attribute unsigned long? selectionEnd;
  [SetterThrows]
           attribute DOMString? selectionDirection;
  // void setRangeText(DOMString replacement);
  // void setRangeText(DOMString replacement, unsigned long start, unsigned long end,
  //                   optional SelectionMode selectionMode = "preserve");
-  void setSelectionRange(unsigned long start, unsigned long end, optional DOMString direction);
+  [Throws]
           void setSelectionRange(unsigned long start, unsigned long end, optional DOMString direction);
 };
--- a/components/script/dom/webidls/PerformanceTiming.webidl
+++ b/components/script/dom/webidls/PerformanceTiming.webidl
@ -29,4 +29,7 @@ interface PerformanceTiming {
  readonly attribute unsigned long long domComplete;
  readonly attribute unsigned long long loadEventStart;
  readonly attribute unsigned long long loadEventEnd;
  /* Servo-onnly attribute for measuring when the top-level document (not iframes) is complete. */
  [Pref="dom.testperf.enabled"]
  readonly attribute unsigned long long topLevelDomComplete;
 };
--- a/components/script/lib.rs
+++ b/components/script/lib.rs
@ -31,6 +31,7 @@ extern crate bluetooth_traits;
 extern crate byteorder;
 extern crate canvas_traits;
 extern crate caseless;
 extern crate chrono;
 extern crate cookie as cookie_rs;
 #[macro_use] extern crate cssparser;
 #[macro_use] extern crate deny_public_fields;
--- a/components/script/textinput.rs
+++ b/components/script/textinput.rs
@ -21,7 +21,7 @@ pub enum Selection {
    NotSelected
 }
-#[derive(Clone, Copy, JSTraceable, MallocSizeOf, PartialEq)]
+#[derive(Clone, Copy, Debug, JSTraceable, MallocSizeOf, PartialEq)]
 pub enum SelectionDirection {
    Forward,
    Backward,
@ -825,7 +825,7 @@ impl<T: ClipboardProvider> TextInput<T> {
        }
    }
-    pub fn set_selection_range(&mut self, start: u32, end: u32) {
+    pub fn set_selection_range(&mut self, start: u32, end: u32, direction: SelectionDirection) {
        let mut start = start as usize;
        let mut end = end as usize;
        let text_end = self.get_content().len();
@ -837,7 +837,9 @@ impl<T: ClipboardProvider> TextInput<T> {
            start = end;
        }
-        match self.selection_direction {
+        self.selection_direction = direction;
        match direction {
            SelectionDirection::None |
            SelectionDirection::Forward => {
                self.selection_begin = Some(self.get_text_point_for_absolute_point(start));
--- a/components/script_traits/script_msg.rs
+++ b/components/script_traits/script_msg.rs
@ -79,7 +79,7 @@ pub enum ScriptMsg {
    ChangeRunningAnimationsState(AnimationState),
    /// Requests that a new 2D canvas thread be created. (This is done in the constellation because
    /// 2D canvases may use the GPU and we don't want to give untrusted content access to the GPU.)
-    CreateCanvasPaintThread(Size2D<i32>, IpcSender<IpcSender<CanvasMsg>>),
+    CreateCanvasPaintThread(Size2D<i32>, IpcReceiver<CanvasMsg>),
    /// Notifies the constellation that this frame has received focus.
    Focus,
    /// Forward an event that was sent to the parent window.
--- a/components/selectors/builder.rs
+++ b/components/selectors/builder.rs
@ -264,12 +264,23 @@ fn complex_selector_specificity<Impl>(mut iter: slice::Iter<Component<Impl>>)
                                      -> Specificity
    where Impl: SelectorImpl
 {
-    fn simple_selector_specificity<Impl>(simple_selector: &Component<Impl>,
+    fn simple_selector_specificity<Impl>(
-                                         specificity: &mut Specificity)
+        simple_selector: &Component<Impl>,
-        where Impl: SelectorImpl
+        specificity: &mut Specificity,
    )
    where
        Impl: SelectorImpl
    {
        match *simple_selector {
            Component::Combinator(..) => unreachable!(),
            // FIXME(emilio): Spec doesn't define any particular specificity for
            // ::slotted(), so apply the general rule for pseudos per:
            //
            // https://github.com/w3c/csswg-drafts/issues/1915
            //
            // Though other engines compute it dynamically, so maybe we should
            // do that instead, eventually.
            Component::Slotted(..) |
            Component::PseudoElement(..) |
            Component::LocalName(..) => {
                specificity.element_selectors += 1
--- a/components/selectors/matching.rs
+++ b/components/selectors/matching.rs
@ -72,14 +72,24 @@ pub fn matches_selector_list<E>(
 where
    E: Element
 {
-    selector_list.0.iter().any(|selector| {
+    // This is pretty much any(..) but manually inlined because the compiler
-        matches_selector(selector,
+    // refuses to do so from querySelector / querySelectorAll.
-                         0,
+    for selector in &selector_list.0 {
-                         None,
+        let matches = matches_selector(
-                         element,
+            selector,
-                         context,
+            0,
-                         &mut |_, _| {})
+            None,
-    })
+            element,
            context,
            &mut |_, _| {},
        );
        if matches {
            return true;
        }
    }
    false
 }
 #[inline(always)]
@ -393,6 +403,9 @@ where
            element.parent_element()
        }
        Combinator::SlotAssignment => {
            element.assigned_slot()
        }
        Combinator::PseudoElement => {
            element.pseudo_element_originating_element()
        }
@ -453,6 +466,7 @@ where
        }
        Combinator::Child |
        Combinator::Descendant |
        Combinator::SlotAssignment |
        Combinator::PseudoElement => {
            SelectorMatchingResult::NotMatchedGlobally
        }
@ -541,6 +555,21 @@ where
 {
    match *selector {
        Component::Combinator(_) => unreachable!(),
        Component::Slotted(ref selectors) => {
            context.shared.nesting_level += 1;
            let result =
                element.assigned_slot().is_some() &&
                selectors.iter().any(|s| {
                    matches_complex_selector(
                        s.iter(),
                        element,
                        context.shared,
                        flags_setter,
                    )
                });
            context.shared.nesting_level -= 1;
            result
        }
        Component::PseudoElement(ref pseudo) => {
            element.match_pseudo_element(pseudo, context.shared)
        }
--- a/components/selectors/parser.rs
+++ b/components/selectors/parser.rs
@ -55,6 +55,7 @@ pub enum SelectorParseErrorKind<'i> {
    EmptySelector,
    DanglingCombinator,
    NonSimpleSelectorInNegation,
    NonCompoundSelector,
    UnexpectedTokenInAttributeSelector(Token<'i>),
    PseudoElementExpectedColon(Token<'i>),
    PseudoElementExpectedIdent(Token<'i>),
@ -127,10 +128,15 @@ pub trait Parser<'i> {
    /// Whether the name is a pseudo-element that can be specified with
    /// the single colon syntax in addition to the double-colon syntax.
-    fn is_pseudo_element_allows_single_colon(name: &CowRcStr<'i>) -> bool {
+    fn pseudo_element_allows_single_colon(name: &str) -> bool {
        is_css2_pseudo_element(name)
    }
    /// Whether to parse the `::slotted()` pseudo-element.
    fn parse_slotted(&self) -> bool {
        false
    }
    /// This function can return an "Err" pseudo-element in order to support CSS2.1
    /// pseudo-elements.
    fn parse_non_ts_pseudo_class(
@ -209,6 +215,33 @@ impl<Impl: SelectorImpl> SelectorList<Impl> {
    }
 }
 /// Parse a comma separated list of compound selectors.
 pub fn parse_compound_selector_list<'i, 't, P, Impl>(
    parser: &P,
    input: &mut CssParser<'i, 't>,
 ) -> Result<Box<[Selector<Impl>]>, ParseError<'i, P::Error>>
 where
    P: Parser<'i, Impl=Impl>,
    Impl: SelectorImpl,
 {
    let location = input.current_source_location();
    let selectors = input.parse_comma_separated(|input| {
        Selector::parse(parser, input)
    })?;
    // Ensure they're actually all compound selectors.
    if selectors
        .iter()
        .flat_map(|x| x.iter_raw_match_order())
        .any(|s| s.is_combinator()) {
        return Err(location.new_custom_error(
            SelectorParseErrorKind::NonCompoundSelector
        ))
    }
    Ok(selectors.into_boxed_slice())
 }
 /// Ancestor hashes for the bloom filter. We precompute these and store them
 /// inline with selectors to optimize cache performance during matching.
 /// This matters a lot.
@ -325,6 +358,13 @@ impl<Impl: SelectorImpl> SelectorMethods for Component<Impl> {
        }
        match *self {
            Slotted(ref selectors) => {
                for selector in selectors.iter() {
                    if !selector.visit(visitor) {
                        return false;
                    }
                }
            }
            Negation(ref negated) => {
                for component in negated.iter() {
                    if !component.visit(visitor) {
@ -630,15 +670,20 @@ pub enum Combinator {
    /// combinator for this, we will need to fix up the way hashes are computed
    /// for revalidation selectors.
    PseudoElement,
    /// Another combinator used for ::slotted(), which represent the jump from
    /// a node to its assigned slot.
    SlotAssignment,
 }
 impl Combinator {
    /// Returns true if this combinator is a child or descendant combinator.
    #[inline]
    pub fn is_ancestor(&self) -> bool {
-        matches!(*self, Combinator::Child |
+        matches!(*self,
-                        Combinator::Descendant |
+                 Combinator::Child |
-                        Combinator::PseudoElement)
+                 Combinator::Descendant |
                 Combinator::PseudoElement |
                 Combinator::SlotAssignment)
    }
    /// Returns true if this combinator is a pseudo-element combinator.
@ -688,16 +733,16 @@ pub enum Component<Impl: SelectorImpl> {
    // Use a Box in the less common cases with more data to keep size_of::<Component>() small.
    AttributeOther(Box<AttrSelectorWithNamespace<Impl>>),
-    // Pseudo-classes
+    /// Pseudo-classes
-    //
+    ///
-    // CSS3 Negation only takes a simple simple selector, but we still need to
+    /// CSS3 Negation only takes a simple simple selector, but we still need to
-    // treat it as a compound selector because it might be a type selector which
+    /// treat it as a compound selector because it might be a type selector
-    // we represent as a namespace and a localname.
+    /// which we represent as a namespace and a localname.
-    //
+    ///
-    // Note: if/when we upgrade this to CSS4, which supports combinators, we
+    /// Note: if/when we upgrade this to CSS4, which supports combinators, we
-    // need to think about how this should interact with visit_complex_selector,
+    /// need to think about how this should interact with
-    // and what the consumers of those APIs should do about the presence of
+    /// visit_complex_selector, and what the consumers of those APIs should do
-    // combinators in negation.
+    /// about the presence of combinators in negation.
    Negation(Box<[Component<Impl>]>),
    FirstChild, LastChild, OnlyChild,
    Root,
@ -711,6 +756,13 @@ pub enum Component<Impl: SelectorImpl> {
    LastOfType,
    OnlyOfType,
    NonTSPseudoClass(Impl::NonTSPseudoClass),
    /// The ::slotted() pseudo-element (which isn't actually a pseudo-element,
    /// and probably should be a pseudo-class):
    ///
    /// https://drafts.csswg.org/css-scoping/#slotted-pseudo
    ///
    /// The selectors here are compound selectors, that is, no combinators.
    Slotted(Box<[Selector<Impl>]>),
    PseudoElement(Impl::PseudoElement),
 }
@ -840,13 +892,15 @@ impl<Impl: SelectorImpl> ToCss for Selector<Impl> {
                let mut perform_step_2 = true;
                if first_non_namespace == compound.len() - 1 {
                    match (combinators.peek(), &compound[first_non_namespace]) {
-                        // We have to be careful here, because if there is a pseudo
+                        // We have to be careful here, because if there is a
-                        // element "combinator" there isn't really just the one
+                        // pseudo element "combinator" there isn't really just
-                        // simple selector. Technically this compound selector
+                        // the one simple selector. Technically this compound
-                        // contains the pseudo element selector as
+                        // selector contains the pseudo element selector as well
-                        // well--Combinator::PseudoElement doesn't exist in the
+                        // -- Combinator::PseudoElement, just like
                        // Combinator::SlotAssignment, don't exist in the
                        // spec.
-                        (Some(&&Component::Combinator(Combinator::PseudoElement)), _) => (),
+                        (Some(&&Component::Combinator(Combinator::PseudoElement)), _) |
                        (Some(&&Component::Combinator(Combinator::SlotAssignment)), _) => (),
                        (_, &Component::ExplicitUniversalType) => {
                            // Iterate over everything so we serialize the namespace
                            // too.
@ -914,6 +968,7 @@ impl ToCss for Combinator {
            Combinator::NextSibling => dest.write_str(" + "),
            Combinator::LaterSibling => dest.write_str(" ~ "),
            Combinator::PseudoElement => Ok(()),
            Combinator::SlotAssignment => Ok(()),
        }
    }
 }
@ -942,6 +997,16 @@ impl<Impl: SelectorImpl> ToCss for Component<Impl> {
            Combinator(ref c) => {
                c.to_css(dest)
            }
            Slotted(ref selectors) => {
                dest.write_str("::slotted(")?;
                let mut iter = selectors.iter();
                iter.next().expect("At least one selector").to_css(dest)?;
                for other in iter {
                    dest.write_str(", ")?;
                    other.to_css(dest)?;
                }
                dest.write_char(')')
            }
            PseudoElement(ref p) => {
                p.to_css(dest)
            }
@ -1092,10 +1157,14 @@ where
    let mut builder = SelectorBuilder::default();
    let mut has_pseudo_element;
    let mut slotted;
    'outer_loop: loop {
        // Parse a sequence of simple selectors.
-        has_pseudo_element = match parse_compound_selector(parser, input, &mut builder)? {
+        match parse_compound_selector(parser, input, &mut builder)? {
-            Some(has_pseudo_element) => has_pseudo_element,
+            Some((has_pseudo, slot)) => {
                has_pseudo_element = has_pseudo;
                slotted = slot;
            }
            None => {
                return Err(input.new_custom_error(if builder.has_combinators() {
                    SelectorParseErrorKind::DanglingCombinator
@ -1104,7 +1173,8 @@ where
                }))
            }
        };
-        if has_pseudo_element {
+
        if has_pseudo_element || slotted {
            break;
        }
@ -1235,6 +1305,7 @@ where
 enum SimpleSelectorParseResult<Impl: SelectorImpl> {
    SimpleSelector(Component<Impl>),
    PseudoElement(Impl::PseudoElement),
    SlottedPseudo(Box<[Selector<Impl>]>),
 }
 #[derive(Debug)]
@ -1547,7 +1618,8 @@ where
            None => {
                return Err(input.new_custom_error(SelectorParseErrorKind::EmptyNegation));
            },
-            Some(SimpleSelectorParseResult::PseudoElement(_)) => {
+            Some(SimpleSelectorParseResult::PseudoElement(_)) |
            Some(SimpleSelectorParseResult::SlottedPseudo(_)) => {
                return Err(input.new_custom_error(SelectorParseErrorKind::NonSimpleSelectorInNegation));
            }
        }
@ -1564,12 +1636,13 @@ where
 /// `Err(())` means invalid selector.
 /// `Ok(None)` is an empty selector
 ///
-/// The boolean represent whether a pseudo-element has been parsed.
+/// The booleans represent whether a pseudo-element has been parsed, and whether
 /// ::slotted() has been parsed, respectively.
 fn parse_compound_selector<'i, 't, P, Impl>(
    parser: &P,
    input: &mut CssParser<'i, 't>,
    builder: &mut SelectorBuilder<Impl>,
-) -> Result<Option<bool>, ParseError<'i, P::Error>>
+) -> Result<Option<(bool, bool)>, ParseError<'i, P::Error>>
 where
    P: Parser<'i, Impl=Impl>,
    Impl: SelectorImpl,
@ -1577,6 +1650,7 @@ where
    input.skip_whitespace();
    let mut empty = true;
    let mut slot = false;
    if !parse_type_selector(parser, input, builder)? {
        if let Some(url) = parser.default_namespace() {
            // If there was no explicit type selector, but there is a
@ -1590,13 +1664,18 @@ where
    let mut pseudo = false;
    loop {
-        match parse_one_simple_selector(parser, input, /* inside_negation = */ false)? {
+        let parse_result =
-            None => break,
+            match parse_one_simple_selector(parser, input, /* inside_negation = */ false)? {
-            Some(SimpleSelectorParseResult::SimpleSelector(s)) => {
+                None => break,
                Some(result) => result,
            };
        match parse_result {
            SimpleSelectorParseResult::SimpleSelector(s) => {
                builder.push_simple_selector(s);
                empty = false
            }
-            Some(SimpleSelectorParseResult::PseudoElement(p)) => {
+            SimpleSelectorParseResult::PseudoElement(p) => {
                // Try to parse state to its right. There are only 3 allowable
                // state selectors that can go on pseudo-elements.
                let mut state_selectors = SmallVec::<[Component<Impl>; 3]>::new();
@ -1645,13 +1724,25 @@ where
                empty = false;
                break
            }
            SimpleSelectorParseResult::SlottedPseudo(selectors) => {
                empty = false;
                slot = true;
                if !builder.is_empty() {
                    builder.push_combinator(Combinator::SlotAssignment);
                }
                builder.push_simple_selector(Component::Slotted(selectors));
                // FIXME(emilio): ::slotted() should support ::before and
                // ::after after it, so we shouldn't break, but we shouldn't
                // push more type selectors either.
                break;
            }
        }
    }
    if empty {
        // An empty selector is invalid.
        Ok(None)
    } else {
-        Ok(Some(pseudo))
+        Ok(Some((pseudo, slot)))
    }
 }
@ -1701,7 +1792,7 @@ where
 /// Returns whether the name corresponds to a CSS2 pseudo-element that
 /// can be specified with the single colon syntax (in addition to the
 /// double-colon syntax, which can be used for all pseudo-elements).
-pub fn is_css2_pseudo_element<'i>(name: &CowRcStr<'i>) -> bool {
+pub fn is_css2_pseudo_element(name: &str) -> bool {
    // ** Do not add to this list! **
    match_ignore_ascii_case! { name,
        "before" | "after" | "first-line" | "first-letter" => true,
@ -1760,16 +1851,35 @@ where
                )),
            };
            let is_pseudo_element = !is_single_colon ||
-                P::is_pseudo_element_allows_single_colon(&name);
+                P::pseudo_element_allows_single_colon(&name);
            if is_pseudo_element {
-                let pseudo_element = if is_functional {
+                let parse_result = if is_functional {
-                    input.parse_nested_block(|input| {
+                    if P::parse_slotted(parser) && name.eq_ignore_ascii_case("slotted") {
-                        P::parse_functional_pseudo_element(parser, name, input)
+                        SimpleSelectorParseResult::SlottedPseudo(
-                    })?
+                            input.parse_nested_block(|input| {
                                parse_compound_selector_list(
                                    parser,
                                    input,
                                )
                            })?
                        )
                    } else {
                        SimpleSelectorParseResult::PseudoElement(
                            input.parse_nested_block(|input| {
                                P::parse_functional_pseudo_element(
                                    parser,
                                    name,
                                    input,
                                )
                            })?
                        )
                    }
                } else {
-                    P::parse_pseudo_element(parser, location, name)?
+                    SimpleSelectorParseResult::PseudoElement(
                        P::parse_pseudo_element(parser, location, name)?
                    )
                };
-                Ok(Some(SimpleSelectorParseResult::PseudoElement(pseudo_element)))
+                Ok(Some(parse_result))
            } else {
                let pseudo_class = if is_functional {
                    input.parse_nested_block(|input| {
@ -1951,6 +2061,10 @@ pub mod tests {
        type Impl = DummySelectorImpl;
        type Error = SelectorParseErrorKind<'i>;
        fn parse_slotted(&self) -> bool {
            true
        }
        fn parse_non_ts_pseudo_class(
            &self,
            location: SourceLocation,
@ -2057,9 +2171,9 @@ pub mod tests {
    #[test]
    fn test_parsing() {
-        assert!(parse("").is_err()) ;
+        assert!(parse("").is_err());
-        assert!(parse(":lang(4)").is_err()) ;
+        assert!(parse(":lang(4)").is_err());
-        assert!(parse(":lang(en US)").is_err()) ;
+        assert!(parse(":lang(en US)").is_err());
        assert_eq!(parse("EeÉ"), Ok(SelectorList::from_vec(vec!(
            Selector::from_vec(vec!(
                Component::LocalName(LocalName {
@ -2366,6 +2480,16 @@ pub mod tests {
                ].into_boxed_slice()
            )), specificity(0, 0, 0))
        ))));
        assert!(parse("::slotted()").is_err());
        assert!(parse("::slotted(div)").is_ok());
        assert!(parse("::slotted(div).foo").is_err());
        assert!(parse("::slotted(div + bar)").is_err());
        assert!(parse("::slotted(div) + foo").is_err());
        assert!(parse("div ::slotted(div)").is_ok());
        assert!(parse("div + slot::slotted(div)").is_ok());
        assert!(parse("div + slot::slotted(div.foo)").is_ok());
        assert!(parse("div + slot::slotted(.foo, bar, .baz)").is_ok());
    }
    #[test]
--- a/components/selectors/tree.rs
+++ b/components/selectors/tree.rs
@ -84,6 +84,13 @@ pub trait Element: Sized + Clone + Debug {
    /// Whether this element is a `link`.
    fn is_link(&self) -> bool;
    /// Returns the assigned <slot> element this element is assigned to.
    ///
    /// Necessary for the `::slotted` pseudo-class.
    fn assigned_slot(&self) -> Option<Self> {
        None
    }
    fn has_id(&self,
              id: &<Self::Impl as SelectorImpl>::Identifier,
              case_sensitivity: CaseSensitivity)
--- a/components/style/animation.rs
+++ b/components/style/animation.rs
@ -339,12 +339,7 @@ impl PropertyAnimation {
            longhand,
            old_style,
            new_style,
-        );
+        )?;
        let animated_property = match animated_property {
            Some(p) => p,
            None => return None,
        };
        let property_animation = PropertyAnimation {
            property: animated_property,
--- a/components/style/bloom.rs
+++ b/components/style/bloom.rs
@ -169,10 +169,8 @@ impl<E: TElement> StyleBloom<E> {
    /// Pop the last element in the bloom filter and return it.
    #[inline]
    fn pop(&mut self) -> Option<E> {
-        let (popped_element, num_hashes)  = match self.elements.pop() {
+        let PushedElement { element, num_hashes } = self.elements.pop()?;
-            None => return None,
+        let popped_element = *element;
            Some(x) => (*x.element, x.num_hashes),
        };
        // Verify that the pushed hashes match the ones we'd get from the element.
        let mut expected_hashes = vec![];
--- a/components/style/build.rs
+++ b/components/style/build.rs
@ -94,6 +94,15 @@ fn generate_properties() {
 }
 fn main() {
    let gecko = cfg!(feature = "gecko");
    let servo = cfg!(feature = "servo");
    if !(gecko || servo) {
        panic!("The style crate requires enabling one of its 'servo' or 'gecko' feature flags");
    }
    if gecko && servo {
        panic!("The style crate does not support enabling both its 'servo' or 'gecko' \
                feature flags at the same time.");
    }
    println!("cargo:rerun-if-changed=build.rs");
    println!("cargo:out_dir={}", env::var("OUT_DIR").unwrap());
    generate_properties();
--- a/components/style/context.rs
+++ b/components/style/context.rs
@ -116,6 +116,21 @@ impl Default for StyleSystemOptions {
    }
 }
 impl StyleSystemOptions {
    #[cfg(feature = "servo")]
    /// On Gecko's nightly build?
    pub fn is_nightly(&self) -> bool {
        false
    }
    #[cfg(feature = "gecko")]
    /// On Gecko's nightly build?
    #[inline]
    pub fn is_nightly(&self) -> bool {
        structs::GECKO_IS_NIGHTLY
    }
 }
 /// A shared style context.
 ///
 /// There's exactly one of these during a given restyle traversal, and it's
--- a/components/style/custom_properties.rs
+++ b/components/style/custom_properties.rs
@ -153,10 +153,7 @@ where
        K: Borrow<Q>,
        Q: PrecomputedHash + Hash + Eq,
    {
-        let index = match self.index.iter().position(|k| k.borrow() == key) {
+        let index = self.index.iter().position(|k| k.borrow() == key)?;
            Some(p) => p,
            None => return None,
        };
        self.index.remove(index);
        self.values.remove(key)
    }
@ -194,10 +191,7 @@ where
    type Item = (&'a K, &'a V);
    fn next(&mut self) -> Option<Self::Item> {
-        let key = match self.inner.index.get(self.pos) {
+        let key = self.inner.index.get(self.pos)?;
            Some(k) => k,
            None => return None,
        };
        self.pos += 1;
        let value = &self.inner.values[key];
--- a/components/style/dom.rs
+++ b/components/style/dom.rs
@ -78,14 +78,10 @@ where
    fn next(&mut self) -> Option<N> {
        loop {
-            match self.0.next() {
+            let n = self.0.next()?;
-                Some(n) => {
+            // Filter out nodes that layout should ignore.
-                    // Filter out nodes that layout should ignore.
+            if n.is_text_node() || n.is_element() {
-                    if n.is_text_node() || n.is_element() {
+                return Some(n)
                        return Some(n)
                    }
                }
                None => return None,
            }
        }
    }
@ -100,13 +96,9 @@ where
    type Item = N;
    fn next(&mut self) -> Option<N> {
-        match self.0.take() {
+        let n = self.0.take()?;
-            Some(n) => {
+        self.0 = n.next_sibling();
-                self.0 = n.next_sibling();
+        Some(n)
                Some(n)
            }
            None => None,
        }
    }
 }
@ -124,11 +116,7 @@ where
    #[inline]
    fn next(&mut self) -> Option<N> {
-        let prev = match self.previous.take() {
+        let prev = self.previous.take()?;
            None => return None,
            Some(n) => n,
        };
        self.previous = prev.next_in_preorder(Some(self.scope));
        self.previous
    }
--- a/components/style/driver.rs
+++ b/components/style/driver.rs
@ -7,7 +7,7 @@
 #![deny(missing_docs)]
-use context::{StyleContext, ThreadLocalStyleContext};
+use context::{StyleContext, ThreadLocalStyleContext, TraversalStatistics};
 use dom::{SendNode, TElement, TNode};
 use parallel;
 use parallel::{DispatchMode, WORK_UNIT_MAX};
@ -25,11 +25,15 @@ use traversal::{DomTraversal, PerLevelTraversalData, PreTraverseToken};
 /// processing, until we arrive at a wide enough level in the DOM that the
 /// parallel traversal would parallelize it. If a thread pool is provided, we
 /// then transfer control over to the parallel traversal.
 ///
 /// Returns true if the traversal was parallel, and also returns the statistics
 /// object containing information on nodes traversed (on nightly only). Not
 /// all of its fields will be initialized since we don't call finish().
 pub fn traverse_dom<E, D>(
    traversal: &D,
    token: PreTraverseToken<E>,
    pool: Option<&rayon::ThreadPool>
-)
+) -> (bool, Option<TraversalStatistics>)
 where
    E: TElement,
    D: DomTraversal<E>,
@ -38,6 +42,8 @@ where
        token.traversal_root().expect("Should've ensured we needed to traverse");
    let dump_stats = traversal.shared_context().options.dump_style_statistics;
    let is_nightly  = traversal.shared_context().options.is_nightly();
    let mut used_parallel = false;
    let start_time = if dump_stats { Some(time::precise_time_s()) } else { None };
    // Declare the main-thread context, as well as the worker-thread contexts,
@ -84,6 +90,7 @@ where
            // moving to the next level in the dom so that we can pass the same
            // depth for all the children.
            if pool.is_some() && discovered.len() > WORK_UNIT_MAX {
                used_parallel = true;
                let pool = pool.unwrap();
                maybe_tls = Some(ScopedTLS::<ThreadLocalStyleContext<E>>::new(pool));
                let root_opaque = root.as_node().opaque();
@ -108,9 +115,9 @@ where
            nodes_remaining_at_current_depth = discovered.len();
        }
    }
-
+    let mut maybe_stats = None;
-    // Dump statistics to stdout if requested.
+    // Accumulate statistics
-    if dump_stats {
+    if dump_stats || is_nightly {
        let mut aggregate =
            mem::replace(&mut context.thread_local.statistics, Default::default());
        let parallel = maybe_tls.is_some();
@ -123,9 +130,14 @@ where
                }
            });
        }
-        aggregate.finish(traversal, parallel, start_time.unwrap());
+
-        if aggregate.is_large_traversal() {
+        // dump to stdout if requested
-            println!("{}", aggregate);
+        if dump_stats && aggregate.is_large_traversal() {
            aggregate.finish(traversal, parallel, start_time.unwrap());
             println!("{}", aggregate);
        }
        maybe_stats = Some(aggregate);
    }
    (used_parallel, maybe_stats)
 }
--- a/components/style/gecko/data.rs
+++ b/components/style/gecko/data.rs
@ -5,6 +5,7 @@
 //! Data needed to style a Gecko document.
 use atomic_refcell::{AtomicRef, AtomicRefCell, AtomicRefMut};
 use context::TraversalStatistics;
 use dom::TElement;
 use gecko_bindings::bindings::{self, RawServoStyleSet};
 use gecko_bindings::structs::{RawGeckoPresContextOwned, ServoStyleSetSizes, ServoStyleSheet};
@ -16,6 +17,7 @@ use media_queries::{Device, MediaList};
 use properties::ComputedValues;
 use servo_arc::Arc;
 use shared_lock::{Locked, StylesheetGuards, SharedRwLockReadGuard};
 use std::sync::atomic::{AtomicUsize, Ordering};
 use stylesheets::{StylesheetContents, StylesheetInDocument};
 use stylist::Stylist;
@ -107,11 +109,40 @@ impl StylesheetInDocument for GeckoStyleSheet {
    }
 }
 #[derive(Default)]
 /// Helper struct for counting traversals
 pub struct TraversalCount {
    /// Total number of events
    pub total_count: AtomicUsize,
    /// Number of events which were parallel
    pub parallel_count: AtomicUsize
 }
 impl TraversalCount {
    fn record(&self, parallel: bool, count: u32) {
        self.total_count.fetch_add(count as usize, Ordering::Relaxed);
        if parallel {
            self.parallel_count.fetch_add(count as usize, Ordering::Relaxed);
        }
    }
    fn get(&self) -> (u32, u32) {
        (self.total_count.load(Ordering::Relaxed) as u32,
         self.parallel_count.load(Ordering::Relaxed) as u32)
    }
 }
 /// The container for data that a Servo-backed Gecko document needs to style
 /// itself.
 pub struct PerDocumentStyleDataImpl {
    /// Rule processor.
    pub stylist: Stylist,
    /// Counter for traversals that could have been parallel, for telemetry
    pub traversal_count: TraversalCount,
    /// Counter for traversals, weighted by elements traversed,
    pub traversal_count_traversed: TraversalCount,
    /// Counter for traversals, weighted by elements styled,
    pub traversal_count_styled: TraversalCount,
 }
 /// The data itself is an `AtomicRefCell`, which guarantees the proper semantics
@ -133,6 +164,9 @@ impl PerDocumentStyleData {
        PerDocumentStyleData(AtomicRefCell::new(PerDocumentStyleDataImpl {
            stylist: Stylist::new(device, quirks_mode.into()),
            traversal_count: Default::default(),
            traversal_count_traversed: Default::default(),
            traversal_count_styled: Default::default(),
        }))
    }
@ -147,6 +181,21 @@ impl PerDocumentStyleData {
    }
 }
 impl Drop for PerDocumentStyleDataImpl {
    fn drop(&mut self) {
        if !structs::GECKO_IS_NIGHTLY {
            return
        }
        let (total, parallel)  = self.traversal_count.get();
        let (total_t, parallel_t)  = self.traversal_count_traversed.get();
        let (total_s, parallel_s)  = self.traversal_count_styled.get();
        unsafe { bindings::Gecko_RecordTraversalStatistics(total, parallel,
                                                           total_t, parallel_t,
                                                           total_s, parallel_s) }
    }
 }
 impl PerDocumentStyleDataImpl {
    /// Recreate the style data if the stylesheets have changed.
    pub fn flush_stylesheets<E>(
@ -209,6 +258,15 @@ impl PerDocumentStyleDataImpl {
    pub fn add_size_of(&self, ops: &mut MallocSizeOfOps, sizes: &mut ServoStyleSetSizes) {
        self.stylist.add_size_of(ops, sizes);
    }
    /// Record that a traversal happened for later collection as telemetry
    pub fn record_traversal(&self, was_parallel: bool, stats: Option<TraversalStatistics>) {
        self.traversal_count.record(was_parallel, 1);
        if let Some(stats) = stats {
            self.traversal_count_traversed.record(was_parallel, stats.elements_traversed);
            self.traversal_count_styled.record(was_parallel, stats.elements_styled);
        }
    }
 }
 unsafe impl HasFFI for PerDocumentStyleData {
--- a/components/style/gecko/generated/bindings.rs
+++ b/components/style/gecko/generated/bindings.rs
@ -499,6 +499,8 @@ extern "C" {
 pub fn Servo_SelectorList_Drop ( ptr : RawServoSelectorListOwned , ) ; 
 } extern "C" {
 pub fn Servo_SourceSizeList_Drop ( ptr : RawServoSourceSizeListOwned , ) ; 
 } extern "C" {
 pub fn Gecko_RecordTraversalStatistics ( total : u32 , parallel : u32 , total_t : u32 , parallel_t : u32 , total_s : u32 , parallel_s : u32 , ) ; 
 } extern "C" {
 pub fn Gecko_IsInDocument ( node : RawGeckoNodeBorrowed , ) -> bool ; 
 } extern "C" {
--- a/components/style/gecko/generated/structs.rs
+++ b/components/style/gecko/generated/structs.rs
--- a/components/style/gecko/selector_parser.rs
+++ b/components/style/gecko/selector_parser.rs
@ -9,9 +9,9 @@ use element_state::{DocumentState, ElementState};
 use gecko_bindings::structs::CSSPseudoClassType;
 use gecko_bindings::structs::RawServoSelectorList;
 use gecko_bindings::sugar::ownership::{HasBoxFFI, HasFFI, HasSimpleFFI};
-use selector_parser::{Direction, SelectorParser, PseudoElementCascadeType};
+use selector_parser::{Direction, SelectorParser};
 use selectors::SelectorList;
-use selectors::parser::{Selector, SelectorMethods, SelectorParseErrorKind};
+use selectors::parser::{self as selector_parser, Selector, SelectorMethods, SelectorParseErrorKind};
 use selectors::visitor::SelectorVisitor;
 use std::fmt;
 use string_cache::{Atom, Namespace, WeakAtom, WeakNamespace};
@ -333,9 +333,10 @@ impl<'a, 'i> ::selectors::Parser<'i> for SelectorParser<'a> {
    type Impl = SelectorImpl;
    type Error = StyleParseErrorKind<'i>;
-    fn is_pseudo_element_allows_single_colon(name: &CowRcStr<'i>) -> bool {
+    fn pseudo_element_allows_single_colon(name: &str) -> bool {
        // FIXME: -moz-tree check should probably be ascii-case-insensitive.
        ::selectors::parser::is_css2_pseudo_element(name) ||
-            name.starts_with("-moz-tree-") // tree pseudo-elements
+            name.starts_with("-moz-tree-")
    }
    fn parse_non_ts_pseudo_class(
@ -399,16 +400,12 @@ impl<'a, 'i> ::selectors::Parser<'i> for SelectorParser<'a> {
                        NonTSPseudoClass::Dir(Box::new(direction))
                    },
                    "-moz-any" => {
-                        let selectors = parser.parse_comma_separated(|input| {
+                        NonTSPseudoClass::MozAny(
-                            Selector::parse(self, input)
+                            selector_parser::parse_compound_selector_list(
-                        })?;
+                                self,
-                        // Selectors inside `:-moz-any` may not include combinators.
+                                parser,
-                        if selectors.iter().flat_map(|x| x.iter_raw_match_order()).any(|s| s.is_combinator()) {
+                            )?
-                            return Err(parser.new_custom_error(
+                        )
                                SelectorParseErrorKind::UnexpectedIdent("-moz-any".into())
                            ))
                        }
                        NonTSPseudoClass::MozAny(selectors.into_boxed_slice())
                    }
                    _ => return Err(parser.new_custom_error(
                        SelectorParseErrorKind::UnsupportedPseudoClassOrElement(name.clone())
@ -431,6 +428,8 @@ impl<'a, 'i> ::selectors::Parser<'i> for SelectorParser<'a> {
    ) -> Result<PseudoElement, ParseError<'i>> {
        PseudoElement::from_slice(&name, self.in_user_agent_stylesheet())
            .or_else(|| {
                // FIXME: -moz-tree check should probably be
                // ascii-case-insensitive.
                if name.starts_with("-moz-tree-") {
                    PseudoElement::tree_pseudo_element(&name, Box::new([]))
                } else {
@ -445,9 +444,10 @@ impl<'a, 'i> ::selectors::Parser<'i> for SelectorParser<'a> {
        name: CowRcStr<'i>,
        parser: &mut Parser<'i, 't>,
    ) -> Result<PseudoElement, ParseError<'i>> {
        // FIXME: -moz-tree check should probably be ascii-case-insensitive.
        if name.starts_with("-moz-tree-") {
-            // Tree pseudo-elements can have zero or more arguments,
+            // Tree pseudo-elements can have zero or more arguments, separated
-            // separated by either comma or space.
+            // by either comma or space.
            let mut args = Vec::new();
            loop {
                let location = parser.current_source_location();
@ -477,12 +477,6 @@ impl<'a, 'i> ::selectors::Parser<'i> for SelectorParser<'a> {
 }
 impl SelectorImpl {
    #[inline]
    /// Legacy alias for PseudoElement::cascade_type.
    pub fn pseudo_element_cascade_type(pseudo: &PseudoElement) -> PseudoElementCascadeType {
        pseudo.cascade_type()
    }
    /// A helper to traverse each eagerly cascaded pseudo-element, executing
    /// `fun` on it.
    #[inline]
--- a/components/style/gecko/wrapper.rs
+++ b/components/style/gecko/wrapper.rs
@ -428,10 +428,7 @@ impl<'lb> GeckoXBLBinding<'lb> {
            if !binding.anon_content().is_null() {
                return Some(binding);
            }
-            binding = match binding.base_binding() {
+            binding = binding.base_binding()?;
                Some(b) => b,
                None => return None,
            };
        }
    }
@ -1006,20 +1003,14 @@ impl<'le> TElement for GeckoElement<'le> {
    fn closest_non_native_anonymous_ancestor(&self) -> Option<Self> {
        debug_assert!(self.is_native_anonymous());
-        let mut parent = match self.traversal_parent() {
+        let mut parent = self.traversal_parent()?;
            Some(e) => e,
            None => return None,
        };
        loop {
            if !parent.is_native_anonymous() {
                return Some(parent);
            }
-            parent = match parent.traversal_parent() {
+            parent = parent.traversal_parent()?;
                Some(p) => p,
                None => return None,
            };
        }
    }
@ -1054,16 +1045,10 @@ impl<'le> TElement for GeckoElement<'le> {
    fn get_smil_override(&self) -> Option<ArcBorrow<Locked<PropertyDeclarationBlock>>> {
        unsafe {
-            let slots = match self.get_extended_slots() {
+            let slots = self.get_extended_slots()?;
                Some(s) => s,
                None => return None,
            };
            let base_declaration: &structs::DeclarationBlock =
-                match slots.mSMILOverrideStyleDeclaration.mRawPtr.as_ref() {
+                slots.mSMILOverrideStyleDeclaration.mRawPtr.as_ref()?;
                    Some(decl) => decl,
                    None => return None,
                };
            assert_eq!(base_declaration.mType, structs::StyleBackendType_Servo);
            let declaration: &structs::ServoDeclarationBlock =
@ -1074,11 +1059,7 @@ impl<'le> TElement for GeckoElement<'le> {
                base_declaration as *const structs::DeclarationBlock
            );
-            let raw: &structs::RawServoDeclarationBlock =
+            let raw: &structs::RawServoDeclarationBlock = declaration.mRaw.mRawPtr.as_ref()?;
                match declaration.mRaw.mRawPtr.as_ref() {
                    Some(decl) => decl,
                    None => return None,
                };
            Some(Locked::<PropertyDeclarationBlock>::as_arc(
                &*(&raw as *const &structs::RawServoDeclarationBlock)
--- a/components/style/invalidation/element/element_wrapper.rs
+++ b/components/style/invalidation/element/element_wrapper.rs
@ -127,10 +127,7 @@ impl<'a, E> ElementWrapper<'a, E>
            if lang.is_some() {
                return lang;
            }
-            match current.parent_element() {
+            current = current.parent_element()?;
                Some(parent) => current = parent,
                None => return None,
            }
        }
    }
 }
--- a/components/style/parser.rs
+++ b/components/style/parser.rs
@ -149,8 +149,10 @@ pub trait Parse : Sized {
    /// Parse a value of this type.
    ///
    /// Returns an error on failure.
-    fn parse<'i, 't>(context: &ParserContext, input: &mut Parser<'i, 't>)
+    fn parse<'i, 't>(
-                     -> Result<Self, ParseError<'i>>;
+        context: &ParserContext,
        input: &mut Parser<'i, 't>,
    ) -> Result<Self, ParseError<'i>>;
 }
 impl<T> Parse for Vec<T>
--- a/components/style/properties/declaration_block.rs
+++ b/components/style/properties/declaration_block.rs
@ -140,14 +140,9 @@ impl<'a> Iterator for NormalDeclarationIterator<'a> {
    fn next(&mut self) -> Option<Self::Item> {
        loop {
-            let next = self.0.iter.next();
+            let (decl, importance) = self.0.iter.next()?;
-            match next {
+            if !importance {
-                Some((decl, importance)) => {
+                return Some(decl);
                    if !importance {
                        return Some(decl);
                    }
                },
                None => return None,
            }
        }
    }
@ -171,7 +166,7 @@ impl<'a, 'cx, 'cx_a:'cx> AnimationValueIterator<'a, 'cx, 'cx_a> {
        declarations: &'a PropertyDeclarationBlock,
        context: &'cx mut Context<'cx_a>,
        default_values: &'a ComputedValues,
-       extra_custom_properties: Option<&'a Arc<::custom_properties::CustomPropertiesMap>>,
+        extra_custom_properties: Option<&'a Arc<::custom_properties::CustomPropertiesMap>>,
    ) -> AnimationValueIterator<'a, 'cx, 'cx_a> {
        AnimationValueIterator {
            iter: declarations.normal_declaration_iter(),
@ -187,11 +182,7 @@ impl<'a, 'cx, 'cx_a:'cx> Iterator for AnimationValueIterator<'a, 'cx, 'cx_a> {
    #[inline]
    fn next(&mut self) -> Option<Self::Item> {
        loop {
-            let next = self.iter.next();
+            let decl = self.iter.next()?;
            let decl = match next {
                Some(decl) => decl,
                None => return None,
            };
            let animation = AnimationValue::from_declaration(
                decl,
--- a/components/style/properties/gecko.mako.rs
+++ b/components/style/properties/gecko.mako.rs
@ -61,6 +61,7 @@ use values::{self, Auto, CustomIdent, Either, KeyframesName, None_};
 use values::computed::{NonNegativeLength, ToComputedValue, Percentage};
 use values::computed::font::{FontSize, SingleFontFamily};
 use values::computed::effects::{BoxShadow, Filter, SimpleShadow};
 use values::computed::outline::OutlineStyle;
 use computed_values::border_style;
 pub mod style_structs {
@ -2348,10 +2349,10 @@ fn static_assert() {
        // cast + static_asserts
        let result = match v {
            % for value in border_style_keyword.values_for('gecko'):
-                Either::Second(border_style::T::${to_camel_case(value)}) =>
+                OutlineStyle::Other(border_style::T::${to_camel_case(value)}) =>
                    structs::${border_style_keyword.gecko_constant(value)} ${border_style_keyword.maybe_cast("u8")},
            % endfor
-                Either::First(Auto) =>
+                OutlineStyle::Auto =>
                    structs::${border_style_keyword.gecko_constant('auto')} ${border_style_keyword.maybe_cast("u8")},
        };
        ${set_gecko_property("mOutlineStyle", "result")}
@ -2378,10 +2379,10 @@ fn static_assert() {
        match ${get_gecko_property("mOutlineStyle")} ${border_style_keyword.maybe_cast("u32")} {
            % for value in border_style_keyword.values_for('gecko'):
            structs::${border_style_keyword.gecko_constant(value)} => {
-                Either::Second(border_style::T::${to_camel_case(value)})
+                OutlineStyle::Other(border_style::T::${to_camel_case(value)})
            },
            % endfor
-            structs::${border_style_keyword.gecko_constant('auto')} => Either::First(Auto),
+            structs::${border_style_keyword.gecko_constant('auto')} => OutlineStyle::Auto,
            % if border_style_keyword.gecko_inexhaustive:
            x => panic!("Found unexpected value in style struct for outline_style property: {:?}", x),
            % endif
@ -3618,11 +3619,11 @@ fn static_assert() {
        if self.gecko.mWillChange.len() == 0 {
            T::Auto
        } else {
-            T::AnimateableFeatures(
+            let custom_idents: Vec<CustomIdent> = self.gecko.mWillChange.iter().map(|gecko_atom| {
-                self.gecko.mWillChange.iter().map(|gecko_atom| {
+                CustomIdent((gecko_atom.mRawPtr as *mut nsAtom).into())
-                    CustomIdent((gecko_atom.mRawPtr as *mut nsAtom).into())
+            }).collect();
-                }).collect()
+
-            )
+            T::AnimateableFeatures(custom_idents.into_boxed_slice())
        }
    }
@ -4228,8 +4229,11 @@ fn static_assert() {
            let ref gecko_quote_values = *self.gecko.mQuotes.mRawPtr;
            longhands::quotes::computed_value::T(
                gecko_quote_values.mQuotePairs.iter().map(|gecko_pair| {
-                    (gecko_pair.first.to_string(), gecko_pair.second.to_string())
+                    (
-                }).collect()
+                        gecko_pair.first.to_string().into_boxed_str(),
                        gecko_pair.second.to_string().into_boxed_str(),
                    )
                }).collect::<Vec<_>>().into_boxed_slice()
            )
        }
    }
--- a/components/style/properties/helpers/animated_properties.mako.rs
+++ b/components/style/properties/helpers/animated_properties.mako.rs
@ -262,7 +262,7 @@ impl AnimatedProperty {
            % for prop in data.longhands:
                % if prop.animatable:
                    AnimatedProperty::${prop.camel_case}(ref from, ref to) => {
-                        // https://w3c.github.io/web-animations/#discrete-animation-type
+                        // https://drafts.csswg.org/web-animations/#discrete-animation-type
                        % if prop.animation_value_type == "discrete":
                            let value = if progress < 0.5 { from.clone() } else { to.clone() };
                        % else:
@ -2833,7 +2833,7 @@ impl ComputeSquaredDistance for AnimatedFilterList {
 ///
 ///   border-top-color, border-color, border-top, border
 ///
-/// [property-order] https://w3c.github.io/web-animations/#calculating-computed-keyframes
+/// [property-order] https://drafts.csswg.org/web-animations/#calculating-computed-keyframes
 #[cfg(feature = "gecko")]
 pub fn compare_property_priority(a: &PropertyId, b: &PropertyId) -> cmp::Ordering {
    match (a.as_shorthand(), b.as_shorthand()) {
--- a/components/style/properties/longhand/box.mako.rs
+++ b/components/style/properties/longhand/box.mako.rs
@ -881,62 +881,14 @@ ${helpers.single_keyword("-moz-orient",
                          spec="Nonstandard (https://developer.mozilla.org/en-US/docs/Web/CSS/-moz-orient)",
                          animation_value_type="discrete")}
-<%helpers:longhand name="will-change" products="gecko" animation_value_type="discrete"
+${helpers.predefined_type(
-                   spec="https://drafts.csswg.org/css-will-change/#will-change">
+    "will-change",
-    use std::fmt;
+    "WillChange",
-    use style_traits::ToCss;
+    "computed::WillChange::auto()",
-    use values::CustomIdent;
+    products="gecko",
-
+    animation_value_type="discrete",
-    pub mod computed_value {
+    spec="https://drafts.csswg.org/css-will-change/#will-change"
-        pub use super::SpecifiedValue as T;
+)}
    }
    #[derive(Clone, Debug, MallocSizeOf, PartialEq, ToComputedValue)]
    pub enum SpecifiedValue {
        Auto,
        AnimateableFeatures(Vec<CustomIdent>),
    }
    impl ToCss for SpecifiedValue {
        fn to_css<W>(&self, dest: &mut W) -> fmt::Result where W: fmt::Write {
            match *self {
                SpecifiedValue::Auto => dest.write_str("auto"),
                SpecifiedValue::AnimateableFeatures(ref features) => {
                    let (first, rest) = features.split_first().unwrap();
                    first.to_css(dest)?;
                    for feature in rest {
                        dest.write_str(", ")?;
                        feature.to_css(dest)?;
                    }
                    Ok(())
                }
            }
        }
    }
    #[inline]
    pub fn get_initial_value() -> computed_value::T {
        computed_value::T::Auto
    }
    /// auto | <animateable-feature>#
    pub fn parse<'i, 't>(_context: &ParserContext, input: &mut Parser<'i, 't>)
                         -> Result<SpecifiedValue, ParseError<'i>> {
        if input.try(|input| input.expect_ident_matching("auto")).is_ok() {
            Ok(computed_value::T::Auto)
        } else {
            input.parse_comma_separated(|i| {
                let location = i.current_source_location();
                CustomIdent::from_ident(location, i.expect_ident()?, &[
                    "will-change",
                    "none",
                    "all",
                    "auto",
                ])
            }).map(SpecifiedValue::AnimateableFeatures)
        }
    }
 </%helpers:longhand>
 ${helpers.predefined_type(
    "shape-image-threshold", "Opacity", "0.0",
--- a/components/style/properties/longhand/list.mako.rs
+++ b/components/style/properties/longhand/list.mako.rs
@ -95,116 +95,19 @@ ${helpers.single_keyword("list-style-position", "outside inside", animation_valu
    </%helpers:longhand>
 % endif
-<%helpers:longhand name="list-style-image" animation_value_type="discrete"
+${helpers.predefined_type("list-style-image",
-                   boxed="${product == 'gecko'}"
+                          "ListStyleImage",
-                   spec="https://drafts.csswg.org/css-lists/#propdef-list-style-image">
+                          initial_value="specified::ListStyleImage::none()",
-    use values::specified::UrlOrNone;
+                          initial_specified_value="specified::ListStyleImage::none()",
-    pub use self::computed_value::T as SpecifiedValue;
+                          animation_value_type="discrete",
                          boxed=product == "gecko",
                          spec="https://drafts.csswg.org/css-lists/#propdef-list-style-image")}
-    pub mod computed_value {
+${helpers.predefined_type("quotes",
-        use values::specified::UrlOrNone;
+                          "Quotes",
-
+                          "computed::Quotes::get_initial_value()",
-        #[derive(Clone, Debug, MallocSizeOf, PartialEq, ToCss)]
+                          animation_value_type="discrete",
-        pub struct T(pub UrlOrNone);
+                          spec="https://drafts.csswg.org/css-content/#propdef-quotes")}
        // FIXME(nox): This is wrong, there are different types for specified
        // and computed URLs in Servo.
        trivial_to_computed_value!(T);
    }
    #[inline]
    pub fn get_initial_value() -> computed_value::T {
        computed_value::T(Either::Second(None_))
    }
    #[inline]
    pub fn get_initial_specified_value() -> SpecifiedValue {
        SpecifiedValue(Either::Second(None_))
    }
    pub fn parse<'i, 't>(context: &ParserContext, input: &mut Parser<'i, 't>)
                         -> Result<SpecifiedValue,ParseError<'i>> {
        % if product == "gecko":
        let mut value = input.try(|input| UrlOrNone::parse(context, input))?;
        if let Either::First(ref mut url) = value {
            url.build_image_value();
        }
        % else :
        let value = input.try(|input| UrlOrNone::parse(context, input))?;
        % endif
        return Ok(SpecifiedValue(value));
    }
 </%helpers:longhand>
 <%helpers:longhand name="quotes" animation_value_type="discrete"
                   spec="https://drafts.csswg.org/css-content/#propdef-quotes">
    use cssparser::serialize_string;
    use std::fmt;
    use style_traits::ToCss;
    pub use self::computed_value::T as SpecifiedValue;
    pub mod computed_value {
        #[derive(Clone, Debug, MallocSizeOf, PartialEq, ToComputedValue)]
        pub struct T(pub Vec<(String, String)>);
    }
    impl ToCss for SpecifiedValue {
        fn to_css<W>(&self, dest: &mut W) -> fmt::Result where W: fmt::Write {
            if self.0.is_empty() {
                return dest.write_str("none")
            }
            let mut first = true;
            for pair in &self.0 {
                if !first {
                    dest.write_str(" ")?;
                }
                first = false;
                serialize_string(&*pair.0, dest)?;
                dest.write_str(" ")?;
                serialize_string(&*pair.1, dest)?;
            }
            Ok(())
        }
    }
    #[inline]
    pub fn get_initial_value() -> computed_value::T {
        computed_value::T(vec![
            ("\u{201c}".to_owned(), "\u{201d}".to_owned()),
            ("\u{2018}".to_owned(), "\u{2019}".to_owned()),
        ])
    }
    pub fn parse<'i, 't>(_: &ParserContext, input: &mut Parser<'i, 't>)
                         -> Result<SpecifiedValue,ParseError<'i>> {
        if input.try(|input| input.expect_ident_matching("none")).is_ok() {
            return Ok(SpecifiedValue(Vec::new()))
        }
        let mut quotes = Vec::new();
        loop {
            let location = input.current_source_location();
            let first = match input.next() {
                Ok(&Token::QuotedString(ref value)) => value.as_ref().to_owned(),
                Ok(t) => return Err(location.new_unexpected_token_error(t.clone())),
                Err(_) => break,
            };
            let location = input.current_source_location();
            let second = match input.next() {
                Ok(&Token::QuotedString(ref value)) => value.as_ref().to_owned(),
                Ok(t) => return Err(location.new_unexpected_token_error(t.clone())),
                Err(e) => return Err(e.into()),
            };
            quotes.push((first, second))
        }
        if !quotes.is_empty() {
            Ok(SpecifiedValue(quotes))
        } else {
            Err(input.new_custom_error(StyleParseErrorKind::UnspecifiedError))
        }
    }
 </%helpers:longhand>
 ${helpers.predefined_type("-moz-image-region",
                          "ClipRectOrAuto",
--- a/components/style/properties/longhand/outline.mako.rs
+++ b/components/style/properties/longhand/outline.mako.rs
@ -20,51 +20,14 @@ ${helpers.predefined_type(
    spec="https://drafts.csswg.org/css-ui/#propdef-outline-color",
 )}
-<%helpers:longhand name="outline-style" animation_value_type="discrete"
+${helpers.predefined_type(
-                   spec="https://drafts.csswg.org/css-ui/#propdef-outline-style">
+    "outline-style",
-    use values::specified::BorderStyle;
+    "OutlineStyle",
-
+    "computed::OutlineStyle::none()",
-    pub type SpecifiedValue = Either<Auto, BorderStyle>;
+    initial_specified_value="specified::OutlineStyle::none()",
-
+    animation_value_type="discrete",
-    impl SpecifiedValue {
+    spec="https://drafts.csswg.org/css-ui/#propdef-outline-style",
-        #[inline]
+)}
        pub fn none_or_hidden(&self) -> bool {
            match *self {
                Either::First(ref _auto) => false,
                Either::Second(ref border_style) => border_style.none_or_hidden()
            }
        }
    }
    #[inline]
    pub fn get_initial_value() -> computed_value::T {
        Either::Second(BorderStyle::None)
    }
    #[inline]
    pub fn get_initial_specified_value() -> SpecifiedValue {
        Either::Second(BorderStyle::None)
    }
    pub mod computed_value {
        pub type T = super::SpecifiedValue;
    }
    pub fn parse<'i, 't>(context: &ParserContext, input: &mut Parser<'i, 't>)
                         -> Result<SpecifiedValue, ParseError<'i>> {
        SpecifiedValue::parse(context, input)
            .and_then(|result| {
                if let Either::Second(BorderStyle::Hidden) = result {
                    // The outline-style property accepts the same values as
                    // border-style, except that 'hidden' is not a legal outline
                    // style.
                    Err(input.new_custom_error(SelectorParseErrorKind::UnexpectedIdent("hidden".into())))
                } else {
                    Ok(result)
                }
            })
    }
 </%helpers:longhand>
 ${helpers.predefined_type("outline-width",
                          "BorderSideWidth",
--- a/components/style/properties/longhand/position.mako.rs
+++ b/components/style/properties/longhand/position.mako.rs
@ -257,7 +257,6 @@ ${helpers.predefined_type("object-position",
                              "computed::NonNegativeLengthOrPercentage::zero()",
                              spec="https://drafts.csswg.org/css-grid/#propdef-grid-%s-gap" % kind,
                              animation_value_type="NonNegativeLengthOrPercentage",
                              gecko_pref="layout.css.grid.enabled",
                              products="gecko")}
    % for range in ["start", "end"]:
@ -267,7 +266,6 @@ ${helpers.predefined_type("object-position",
                                  animation_value_type="discrete",
                                  spec="https://drafts.csswg.org/css-grid/#propdef-grid-%s-%s" % (kind, range),
                                  products="gecko",
                                  gecko_pref="layout.css.grid.enabled",
                                  boxed=True)}
    % endfor
@ -279,7 +277,6 @@ ${helpers.predefined_type("object-position",
                              animation_value_type="discrete",
                              spec="https://drafts.csswg.org/css-grid/#propdef-grid-auto-%ss" % kind,
                              products="gecko",
                              gecko_pref="layout.css.grid.enabled",
                              boxed=True)}
    ${helpers.predefined_type("grid-template-%ss" % kind,
@ -288,7 +285,6 @@ ${helpers.predefined_type("object-position",
                              products="gecko",
                              spec="https://drafts.csswg.org/css-grid/#propdef-grid-template-%ss" % kind,
                              boxed=True,
                              gecko_pref="layout.css.grid.enabled",
                              animation_value_type="discrete")}
 % endfor
@ -298,7 +294,6 @@ ${helpers.predefined_type("grid-auto-flow",
                          initial_value="computed::GridAutoFlow::row()",
                          products="gecko",
                          animation_value_type="discrete",
                          gecko_pref="layout.css.grid.enabled",
                          spec="https://drafts.csswg.org/css-grid/#propdef-grid-auto-flow")}
 ${helpers.predefined_type("grid-template-areas",
@ -306,6 +301,5 @@ ${helpers.predefined_type("grid-template-areas",
                          initial_value="computed::GridTemplateAreas::none()",
                          products="gecko",
                          animation_value_type="discrete",
                          gecko_pref="layout.css.grid.enabled",
                          boxed=True,
                          spec="https://drafts.csswg.org/css-grid/#propdef-grid-template-areas")}
--- a/components/style/properties/properties.mako.rs
+++ b/components/style/properties/properties.mako.rs
@ -850,11 +850,13 @@ impl ShorthandId {
    /// Finds and returns an appendable value for the given declarations.
    ///
    /// Returns the optional appendable value.
-    pub fn get_shorthand_appendable_value<'a, I>(self,
+    pub fn get_shorthand_appendable_value<'a, I>(
-                                                 declarations: I)
+        self,
-                                                 -> Option<AppendableValue<'a, I::IntoIter>>
+        declarations: I,
-        where I: IntoIterator<Item=&'a PropertyDeclaration>,
+    ) -> Option<AppendableValue<'a, I::IntoIter>>
-              I::IntoIter: Clone,
+    where
        I: IntoIterator<Item=&'a PropertyDeclaration>,
        I::IntoIter: Clone,
    {
        let declarations = declarations.into_iter();
@ -862,10 +864,7 @@ impl ShorthandId {
        let mut declarations2 = declarations.clone();
        let mut declarations3 = declarations.clone();
-        let first_declaration = match declarations2.next() {
+        let first_declaration = declarations2.next()?;
            Some(declaration) => declaration,
            None => return None
        };
        // https://drafts.csswg.org/css-variables/#variables-in-shorthands
        if let Some(css) = first_declaration.with_variables_from_shorthand(self) {
--- a/components/style/properties/shorthand/position.mako.rs
+++ b/components/style/properties/shorthand/position.mako.rs
@ -103,7 +103,6 @@
 </%helpers:shorthand>
 <%helpers:shorthand name="grid-gap" sub_properties="grid-row-gap grid-column-gap"
                    gecko_pref="layout.css.grid.enabled"
                    spec="https://drafts.csswg.org/css-grid/#propdef-grid-gap"
                    products="gecko">
  use properties::longhands::{grid_row_gap, grid_column_gap};
@ -135,7 +134,6 @@
 % for kind in ["row", "column"]:
 <%helpers:shorthand name="grid-${kind}" sub_properties="grid-${kind}-start grid-${kind}-end"
                    gecko_pref="layout.css.grid.enabled"
                    spec="https://drafts.csswg.org/css-grid/#propdef-grid-${kind}"
                    products="gecko">
    use values::specified::GridLine;
@ -175,7 +173,6 @@
 % endfor
 <%helpers:shorthand name="grid-area"
                    gecko_pref="layout.css.grid.enabled"
                    sub_properties="grid-row-start grid-row-end grid-column-start grid-column-end"
                    spec="https://drafts.csswg.org/css-grid/#propdef-grid-area"
                    products="gecko">
@ -241,7 +238,6 @@
 </%helpers:shorthand>
 <%helpers:shorthand name="grid-template"
                    gecko_pref="layout.css.grid.enabled"
                    sub_properties="grid-template-rows grid-template-columns grid-template-areas"
                    spec="https://drafts.csswg.org/css-grid/#propdef-grid-template"
                    products="gecko">
@ -463,7 +459,6 @@
 </%helpers:shorthand>
 <%helpers:shorthand name="grid"
                    gecko_pref="layout.css.grid.enabled"
                    sub_properties="grid-template-rows grid-template-columns grid-template-areas
                                    grid-auto-rows grid-auto-columns grid-auto-flow"
                    spec="https://drafts.csswg.org/css-grid/#propdef-grid"
--- a/components/style/rule_cache.rs
+++ b/components/style/rule_cache.rs
@ -102,20 +102,16 @@ impl RuleCache {
            return None;
        }
-        let rules = match builder_with_early_props.rules {
+        let rules = builder_with_early_props.rules.as_ref()?;
-            Some(ref rules) => rules,
+        let cached_values = self.map.get(rules)?;
            None => return None,
        };
-        self.map.get(rules).and_then(|cached_values| {
+        for &(ref conditions, ref values) in cached_values.iter() {
-            for &(ref conditions, ref values) in cached_values.iter() {
+            if conditions.matches(builder_with_early_props) {
-                if conditions.matches(builder_with_early_props) {
+                debug!("Using cached reset style with conditions {:?}", conditions);
-                    debug!("Using cached reset style with conditions {:?}", conditions);
+                return Some(&**values)
                    return Some(&**values)
                }
            }
-            None
+        }
-        })
+        None
    }
    /// Inserts a node into the rules cache if possible.
--- a/components/style/servo/selector_parser.rs
+++ b/components/style/servo/selector_parser.rs
@ -547,12 +547,6 @@ impl<'a, 'i> ::selectors::Parser<'i> for SelectorParser<'a> {
 }
 impl SelectorImpl {
    /// Returns the pseudo-element cascade type of the given `pseudo`.
    #[inline]
    pub fn pseudo_element_cascade_type(pseudo: &PseudoElement) -> PseudoElementCascadeType {
        pseudo.cascade_type()
    }
    /// A helper to traverse each eagerly cascaded pseudo-element, executing
    /// `fun` on it.
    #[inline]
--- a/components/style/style_resolver.rs
+++ b/components/style/style_resolver.rs
@ -376,11 +376,7 @@ where
            originating_element_style.style(),
            pseudo,
            VisitedHandlingMode::AllLinksUnvisited
-        );
+        )?;
        let rules = match rules {
            Some(rules) => rules,
            None => return None,
        };
        let mut visited_rules = None;
        if originating_element_style.style().visited_style().is_some() {
--- a/components/style/stylesheet_set.rs
+++ b/components/style/stylesheet_set.rs
@ -80,10 +80,7 @@ where
    fn next(&mut self) -> Option<Self::Item> {
        loop {
            if self.current.is_none() {
-                let next_origin = match self.origins.next() {
+                let next_origin = self.origins.next()?;
                    Some(o) => o,
                    None => return None,
                };
                self.current =
                    Some((next_origin, self.collections.borrow_for_origin(&next_origin).iter()));
@ -238,10 +235,7 @@ where
        use std::mem;
        loop {
-            let potential_sheet = match self.iter.next() {
+            let potential_sheet = self.iter.next()?;
                Some(s) => s,
                None => return None,
            };
            let dirty = mem::replace(&mut potential_sheet.dirty, false);
            if dirty {
--- a/components/style/stylesheets/origin.rs
+++ b/components/style/stylesheets/origin.rs
@ -89,10 +89,7 @@ impl Iterator for OriginSetIterator {
    fn next(&mut self) -> Option<Origin> {
        loop {
-            let origin = match Origin::from_index(self.cur) {
+            let origin = Origin::from_index(self.cur)?;
                Some(origin) => origin,
                None => return None,
            };
            self.cur += 1;
@ -184,10 +181,7 @@ impl<'a, T> Iterator for PerOriginIter<'a, T> where T: 'a {
    type Item = (&'a T, Origin);
    fn next(&mut self) -> Option<Self::Item> {
-        let origin = match Origin::from_index(self.cur) {
+        let origin = Origin::from_index(self.cur)?;
            Some(origin) => origin,
            None => return None,
        };
        self.cur += if self.rev { -1 } else { 1 };
@ -211,10 +205,7 @@ impl<'a, T> Iterator for PerOriginIterMut<'a, T> where T: 'a {
    type Item = (&'a mut T, Origin);
    fn next(&mut self) -> Option<Self::Item> {
-        let origin = match Origin::from_index(self.cur) {
+        let origin = Origin::from_index(self.cur)?;
            Some(origin) => origin,
            None => return None,
        };
        self.cur += 1;
--- a/components/style/stylist.rs
+++ b/components/style/stylist.rs
@ -196,11 +196,7 @@ impl<'a> Iterator for DocumentCascadeDataIter<'a> {
    type Item = (&'a CascadeData, Origin);
    fn next(&mut self) -> Option<Self::Item> {
-        let (_, origin) = match self.iter.next() {
+        let (_, origin) = self.iter.next()?;
            Some(o) => o,
            None => return None,
        };
        Some((self.cascade_data.borrow_for_origin(origin), origin))
    }
 }
@ -670,7 +666,7 @@ impl Stylist {
            parent,
            cascade_flags,
            font_metrics,
-            &rule_node
+            rule_node
        )
    }
@ -683,37 +679,19 @@ impl Stylist {
        parent: Option<&ComputedValues>,
        cascade_flags: CascadeFlags,
        font_metrics: &FontMetricsProvider,
-        rule_node: &StrongRuleNode
+        rule_node: StrongRuleNode
    ) -> Arc<ComputedValues> {
-        // NOTE(emilio): We skip calculating the proper layout parent style
+        self.compute_pseudo_element_style_with_inputs(
-        // here.
+            &CascadeInputs {
-        //
+                rules: Some(rule_node),
-        // It'd be fine to assert that this isn't called with a parent style
+                visited_rules: None,
-        // where display contents is in effect, but in practice this is hard to
+            },
-        // do for stuff like :-moz-fieldset-content with a
+            pseudo,
        // <fieldset style="display: contents">. That is, the computed value of
        // display for the fieldset is "contents", even though it's not the used
        // value, so we don't need to adjust in a different way anyway.
        //
        // In practice, I don't think any anonymous content can be a direct
        // descendant of a display: contents element where display: contents is
        // the actual used value, and the computed value of it would need
        // blockification.
        properties::cascade(
            &self.device,
            Some(pseudo),
            rule_node,
            guards,
            parent,
            parent,
            parent,
            None,
            font_metrics,
            cascade_flags,
-            self.quirks_mode,
+        ).unwrap()
            /* rule_cache = */ None,
            &mut Default::default(),
        )
    }
    /// Returns the rule node for given precomputed pseudo-element.
@ -839,8 +817,9 @@ impl Stylist {
            &cascade_inputs,
            pseudo,
            guards,
-            parent_style,
+            Some(parent_style),
            font_metrics,
            CascadeFlags::empty(),
        )
    }
@ -853,8 +832,9 @@ impl Stylist {
        inputs: &CascadeInputs,
        pseudo: &PseudoElement,
        guards: &StylesheetGuards,
-        parent_style: &ComputedValues,
+        parent_style: Option<&ComputedValues>,
-        font_metrics: &FontMetricsProvider
+        font_metrics: &FontMetricsProvider,
        cascade_flags: CascadeFlags,
    ) -> Option<Arc<ComputedValues>> {
        // We may have only visited rules in cases when we are actually
        // resolving, not probing, pseudo-element style.
@ -867,6 +847,13 @@ impl Stylist {
        // pseudos other than before and after, so it's probably ok.
        //
        // (Though the flags don't indicate so!)
        //
        // It'd be fine to assert that this isn't called with a parent style
        // where display contents is in effect, but in practice this is hard to
        // do for stuff like :-moz-fieldset-content with a
        // <fieldset style="display: contents">. That is, the computed value of
        // display for the fieldset is "contents", even though it's not the used
        // value, so we don't need to adjust in a different way anyway.
        Some(self.compute_style_with_inputs(
            inputs,
            Some(pseudo),
@ -875,7 +862,7 @@ impl Stylist {
            parent_style,
            parent_style,
            font_metrics,
-            CascadeFlags::empty(),
+            cascade_flags,
        ))
    }
@ -899,15 +886,18 @@ impl Stylist {
        inputs: &CascadeInputs,
        pseudo: Option<&PseudoElement>,
        guards: &StylesheetGuards,
-        parent_style: &ComputedValues,
+        parent_style: Option<&ComputedValues>,
-        parent_style_ignoring_first_line: &ComputedValues,
+        parent_style_ignoring_first_line: Option<&ComputedValues>,
-        layout_parent_style: &ComputedValues,
+        layout_parent_style: Option<&ComputedValues>,
        font_metrics: &FontMetricsProvider,
        cascade_flags: CascadeFlags
    ) -> Arc<ComputedValues> {
        // We need to compute visited values if we have visited rules or if our
        // parent has visited values.
-        let visited_values = if inputs.visited_rules.is_some() || parent_style.visited_style().is_some() {
+        let mut visited_values = None;
        if inputs.visited_rules.is_some() ||
            parent_style.and_then(|s| s.visited_style()).is_some()
        {
            // At this point inputs may have visited rules, or rules, or both,
            // or neither (e.g. if it's a text style it may have neither).  So
            // we have to be a bit careful here.
@ -927,31 +917,35 @@ impl Stylist {
                // We want to use the visited bits (if any) from our parent
                // style as our parent.
                inherited_style =
-                    parent_style.visited_style().unwrap_or(parent_style);
+                    parent_style.map(|parent_style| {
                        parent_style.visited_style().unwrap_or(parent_style)
                    });
                inherited_style_ignoring_first_line =
-                    parent_style_ignoring_first_line.visited_style().unwrap_or(parent_style_ignoring_first_line);
+                    parent_style_ignoring_first_line.map(|parent_style| {
                        parent_style.visited_style().unwrap_or(parent_style)
                    });
                layout_parent_style_for_visited =
-                    layout_parent_style.visited_style().unwrap_or(layout_parent_style);
+                    layout_parent_style.map(|parent_style| {
                        parent_style.visited_style().unwrap_or(parent_style)
                    });
            }
-            Some(properties::cascade(
+            visited_values = Some(properties::cascade(
                &self.device,
                pseudo,
                rule_node,
                guards,
-                Some(inherited_style),
+                inherited_style,
-                Some(inherited_style_ignoring_first_line),
+                inherited_style_ignoring_first_line,
-                Some(layout_parent_style_for_visited),
+                layout_parent_style_for_visited,
                None,
                font_metrics,
                cascade_flags | CascadeFlags::VISITED_DEPENDENT_ONLY,
                self.quirks_mode,
                /* rule_cache = */ None,
                &mut Default::default(),
-            ))
+            ));
-        } else {
+        }
            None
        };
        // We may not have non-visited rules, if we only had visited ones.  In
        // that case we want to use the root rulenode for our non-visited rules.
@ -966,9 +960,9 @@ impl Stylist {
            pseudo,
            rules,
            guards,
-            Some(parent_style),
+            parent_style,
-            Some(parent_style_ignoring_first_line),
+            parent_style_ignoring_first_line,
-            Some(layout_parent_style),
+            layout_parent_style,
            visited_values,
            font_metrics,
            cascade_flags,
@ -1232,7 +1226,10 @@ impl Stylist {
        debug!("Determining if style is shareable: pseudo: {}",
               pseudo_element.is_some());
-        let only_default_rules = rule_inclusion == RuleInclusion::DefaultOnly;
+        let only_default_rules =
            rule_inclusion == RuleInclusion::DefaultOnly;
        let matches_user_and_author_rules =
            rule_hash_target.matches_user_and_author_rules();
        // Step 1: Normal user-agent rules.
        if let Some(map) = self.cascade_data.user_agent.cascade_data.borrow_for_pseudo(pseudo_element) {
@ -1271,7 +1268,7 @@ impl Stylist {
        //      rule_hash_target.matches_user_and_author_rules())
        //
        // Which may be more what you would probably expect.
-        if rule_hash_target.matches_user_and_author_rules() {
+        if matches_user_and_author_rules {
            // Step 3a: User normal rules.
            if let Some(map) = self.cascade_data.user.borrow_for_pseudo(pseudo_element) {
                map.get_all_matching_rules(
@ -1315,24 +1312,20 @@ impl Stylist {
            }
        });
-        if rule_hash_target.matches_user_and_author_rules() && !only_default_rules {
+        if matches_user_and_author_rules && !only_default_rules &&
-            // Gecko skips author normal rules if cutting off inheritance.
+            !cut_off_inheritance
-            // See nsStyleSet::FileRules().
+        {
-            if !cut_off_inheritance {
+            // Step 3c: Author normal rules.
-                // Step 3c: Author normal rules.
+            if let Some(map) = self.cascade_data.author.borrow_for_pseudo(pseudo_element) {
-                if let Some(map) = self.cascade_data.author.borrow_for_pseudo(pseudo_element) {
+                map.get_all_matching_rules(
-                    map.get_all_matching_rules(
+                    element,
-                        element,
+                    &rule_hash_target,
-                        &rule_hash_target,
+                    applicable_declarations,
-                        applicable_declarations,
+                    context,
-                        context,
+                    self.quirks_mode,
-                        self.quirks_mode,
+                    flags_setter,
-                        flags_setter,
+                    CascadeLevel::AuthorNormal
-                        CascadeLevel::AuthorNormal
+                );
                    );
                }
            } else {
                debug!("skipping author normal rules due to cut off inheritance");
            }
        } else {
            debug!("skipping author normal rules");
--- a/components/style/values/animated/mod.rs
+++ b/components/style/values/animated/mod.rs
@ -48,15 +48,15 @@ pub trait Animate: Sized {
 /// An animation procedure.
 ///
-/// <https://w3c.github.io/web-animations/#procedures-for-animating-properties>
+/// <https://drafts.csswg.org/web-animations/#procedures-for-animating-properties>
 #[allow(missing_docs)]
 #[derive(Clone, Copy, Debug, PartialEq)]
 pub enum Procedure {
-    /// <https://w3c.github.io/web-animations/#animation-interpolation>
+    /// <https://drafts.csswg.org/web-animations/#animation-interpolation>
    Interpolate { progress: f64 },
-    /// <https://w3c.github.io/web-animations/#animation-addition>
+    /// <https://drafts.csswg.org/web-animations/#animation-addition>
    Add,
-    /// <https://w3c.github.io/web-animations/#animation-accumulation>
+    /// <https://drafts.csswg.org/web-animations/#animation-accumulation>
    Accumulate { count: u64 },
 }
--- a/components/style/values/computed/box.rs
+++ b/components/style/values/computed/box.rs
@ -9,7 +9,8 @@ use values::computed::length::LengthOrPercentage;
 use values::generics::box_::AnimationIterationCount as GenericAnimationIterationCount;
 use values::generics::box_::VerticalAlign as GenericVerticalAlign;
-pub use values::specified::box_::{AnimationName, OverflowClipBox, OverscrollBehavior, ScrollSnapType};
+pub use values::specified::box_::{AnimationName, OverflowClipBox, OverscrollBehavior};
 pub use values::specified::box_::{ScrollSnapType, WillChange};
 /// A computed value for the `vertical-align` property.
 pub type VerticalAlign = GenericVerticalAlign<LengthOrPercentage>;
--- a/components/style/values/computed/list.rs
+++ b/components/style/values/computed/list.rs
@ -0,0 +1,26 @@
 /* This Source Code Form is subject to the terms of the Mozilla Public
 * License, v. 2.0. If a copy of the MPL was not distributed with this
 * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
 //! `list` computed values.
 pub use values::specified::list::{ListStyleImage, Quotes};
 impl Quotes {
    /// Initial value for `quotes`.
    ///
    /// FIXME(emilio): This should ideally not allocate.
    #[inline]
    pub fn get_initial_value() -> Quotes {
        Quotes(vec![
            (
                "\u{201c}".to_owned().into_boxed_str(),
                "\u{201d}".to_owned().into_boxed_str(),
            ),
            (
                "\u{2018}".to_owned().into_boxed_str(),
                "\u{2019}".to_owned().into_boxed_str(),
            ),
        ].into_boxed_slice())
    }
 }
--- a/components/style/values/computed/mod.rs
+++ b/components/style/values/computed/mod.rs
@ -41,7 +41,7 @@ pub use self::font::{FontFamily, FontLanguageOverride, FontVariantSettings, Font
 pub use self::font::{FontVariantLigatures, FontVariantNumeric, FontFeatureSettings};
 pub use self::font::{MozScriptLevel, MozScriptMinSize, MozScriptSizeMultiplier, XTextZoom, XLang};
 pub use self::box_::{AnimationIterationCount, AnimationName, OverscrollBehavior};
-pub use self::box_::{OverflowClipBox, ScrollSnapType, VerticalAlign};
+pub use self::box_::{OverflowClipBox, ScrollSnapType, VerticalAlign, WillChange};
 pub use self::color::{Color, ColorPropertyValue, RGBAColor};
 pub use self::effects::{BoxShadow, Filter, SimpleShadow};
 pub use self::flex::FlexBasis;
@ -54,6 +54,8 @@ pub use super::specified::{BorderStyle, TextDecorationLine};
 pub use self::length::{CalcLengthOrPercentage, Length, LengthOrNone, LengthOrNumber, LengthOrPercentage};
 pub use self::length::{LengthOrPercentageOrAuto, LengthOrPercentageOrNone, MaxLength, MozLength};
 pub use self::length::{CSSPixelLength, NonNegativeLength, NonNegativeLengthOrPercentage};
 pub use self::list::{ListStyleImage, Quotes};
 pub use self::outline::OutlineStyle;
 pub use self::percentage::Percentage;
 pub use self::position::{Position, GridAutoFlow, GridTemplateAreas};
 pub use self::svg::{SVGLength, SVGOpacity, SVGPaint, SVGPaintKind, SVGStrokeDashArray, SVGWidth};
@ -79,6 +81,8 @@ pub mod image;
 #[cfg(feature = "gecko")]
 pub mod gecko;
 pub mod length;
 pub mod list;
 pub mod outline;
 pub mod percentage;
 pub mod position;
 pub mod rect;
@ -397,6 +401,7 @@ trivial_to_computed_value!(BorderStyle);
 trivial_to_computed_value!(Cursor);
 trivial_to_computed_value!(Namespace);
 trivial_to_computed_value!(String);
 trivial_to_computed_value!(Box<str>);
 /// A `<number>` value.
 pub type Number = CSSFloat;
--- a/components/style/values/computed/outline.rs
+++ b/components/style/values/computed/outline.rs
@ -0,0 +1,7 @@
 /* This Source Code Form is subject to the terms of the Mozilla Public
 * License, v. 2.0. If a copy of the MPL was not distributed with this
 * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
 //! Computed values for outline properties
 pub use values::specified::OutlineStyle;
--- a/components/style/values/generics/grid.rs
+++ b/components/style/values/generics/grid.rs
@ -59,12 +59,16 @@ where
        }
        if let Some(ref i) = self.line_num {
-            dest.write_str(" ")?;
+            if self.is_span {
                dest.write_str(" ")?;
            }
            i.to_css(dest)?;
        }
        if let Some(ref s) = self.ident {
-            dest.write_str(" ")?;
+            if self.is_span || self.line_num.is_some() {
                dest.write_str(" ")?;
            }
            s.to_css(dest)?;
        }
--- a/components/style/values/specified/background.rs
+++ b/components/style/values/specified/background.rs
@ -46,11 +46,13 @@ impl BackgroundSize {
 }
 /// One of the keywords for `background-repeat`.
-define_css_keyword_enum! { RepeatKeyword:
+#[derive(Clone, Copy, Debug, Eq, MallocSizeOf, Parse, PartialEq, ToComputedValue, ToCss)]
-    "repeat" => Repeat,
+#[allow(missing_docs)]
-    "space" => Space,
+pub enum RepeatKeyword {
-    "round" => Round,
+    Repeat,
-    "no-repeat" => NoRepeat
+    Space,
    Round,
    NoRepeat,
 }
 /// The specified value for the `background-repeat` property.
--- a/components/style/values/specified/box.rs
+++ b/components/style/values/specified/box.rs
@ -9,6 +9,7 @@ use cssparser::Parser;
 use parser::{Parse, ParserContext};
 use std::fmt;
 use style_traits::{ParseError, ToCss};
 use values::CustomIdent;
 use values::KeyframesName;
 use values::generics::box_::AnimationIterationCount as GenericAnimationIterationCount;
 use values::generics::box_::VerticalAlign as GenericVerticalAlign;
@ -130,3 +131,49 @@ define_css_keyword_enum! { OverflowClipBox:
    "content-box" => ContentBox,
 }
 add_impls_for_keyword_enum!(OverflowClipBox);
 #[derive(Clone, Debug, MallocSizeOf, PartialEq, ToComputedValue, ToCss)]
 /// Provides a rendering hint to the user agent,
 /// stating what kinds of changes the author expects
 /// to perform on the element
 ///
 /// <https://drafts.csswg.org/css-will-change/#will-change>
 pub enum WillChange {
    /// Expresses no particular intent
    Auto,
    #[css(comma, iterable)]
    /// <custom-ident>
    AnimateableFeatures(Box<[CustomIdent]>),
 }
 impl WillChange {
    #[inline]
    /// Get default value of `will-change` as `auto`
    pub fn auto() -> WillChange {
        WillChange::Auto
    }
 }
 impl Parse for WillChange {
    /// auto | <animateable-feature>#
    fn parse<'i, 't>(
        _context: &ParserContext,
        input: &mut Parser<'i, 't>
    ) -> Result<WillChange, ParseError<'i>> {
        if input.try(|input| input.expect_ident_matching("auto")).is_ok() {
            return Ok(WillChange::Auto);
        }
        let custom_idents = input.parse_comma_separated(|i| {
            let location = i.current_source_location();
            CustomIdent::from_ident(location, i.expect_ident()?, &[
                "will-change",
                "none",
                "all",
                "auto",
            ])
        })?;
        Ok(WillChange::AnimateableFeatures(custom_idents.into_boxed_slice()))
    }
 }
--- a/components/style/values/specified/list.rs
+++ b/components/style/values/specified/list.rs
@ -0,0 +1,106 @@
 /* This Source Code Form is subject to the terms of the Mozilla Public
 * License, v. 2.0. If a copy of the MPL was not distributed with this
 * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
 //! `list` specified values.
 use cssparser::{Parser, Token};
 use parser::{Parse, ParserContext};
 use std::fmt;
 use style_traits::{ParseError, StyleParseErrorKind, ToCss};
 use values::{Either, None_};
 use values::specified::UrlOrNone;
 /// Specified and computed `list-style-image` property.
 #[derive(Clone, Debug, MallocSizeOf, PartialEq, ToCss)]
 pub struct ListStyleImage(pub UrlOrNone);
 // FIXME(nox): This is wrong, there are different types for specified
 // and computed URLs in Servo.
 trivial_to_computed_value!(ListStyleImage);
 impl ListStyleImage {
    /// Initial specified value for `list-style-image`.
    #[inline]
    pub fn none() -> ListStyleImage {
        ListStyleImage(Either::Second(None_))
    }
 }
 impl Parse for ListStyleImage {
    fn parse<'i, 't>(context: &ParserContext, input: &mut Parser<'i, 't>)
                         -> Result<ListStyleImage, ParseError<'i>> {
        #[allow(unused_mut)]
        let mut value = input.try(|input| UrlOrNone::parse(context, input))?;
        #[cfg(feature = "gecko")]
        {
            if let Either::First(ref mut url) = value {
                url.build_image_value();
            }
        }
        return Ok(ListStyleImage(value));
    }
 }
 /// Specified and computed `quote` property.
 ///
 /// FIXME(emilio): It's a shame that this allocates all the time it's computed,
 /// probably should just be refcounted.
 #[derive(Clone, Debug, MallocSizeOf, PartialEq, ToComputedValue)]
 pub struct Quotes(pub Box<[(Box<str>, Box<str>)]>);
 impl ToCss for Quotes {
    fn to_css<W>(&self, dest: &mut W) -> fmt::Result where W: fmt::Write {
        let mut iter = self.0.iter();
        match iter.next() {
            Some(&(ref l, ref r)) => {
                l.to_css(dest)?;
                dest.write_char(' ')?;
                r.to_css(dest)?;
            }
            None => return dest.write_str("none"),
        }
        for &(ref l, ref r) in iter {
            dest.write_char(' ')?;
            l.to_css(dest)?;
            dest.write_char(' ')?;
            r.to_css(dest)?;
        }
        Ok(())
    }
 }
 impl Parse for Quotes {
    fn parse<'i, 't>(_: &ParserContext, input: &mut Parser<'i, 't>) -> Result<Quotes, ParseError<'i>> {
        if input.try(|input| input.expect_ident_matching("none")).is_ok() {
            return Ok(Quotes(Vec::new().into_boxed_slice()))
        }
        let mut quotes = Vec::new();
        loop {
            let location = input.current_source_location();
            let first = match input.next() {
                Ok(&Token::QuotedString(ref value)) => {
                    value.as_ref().to_owned().into_boxed_str()
                },
                Ok(t) => return Err(location.new_unexpected_token_error(t.clone())),
                Err(_) => break,
            };
            let second =
                input.expect_string()?.as_ref().to_owned().into_boxed_str();
            quotes.push((first, second))
        }
        if !quotes.is_empty() {
            Ok(Quotes(quotes.into_boxed_slice()))
        } else {
            Err(input.new_custom_error(StyleParseErrorKind::UnspecifiedError))
        }
    }
 }
--- a/components/style/values/specified/mod.rs
+++ b/components/style/values/specified/mod.rs
@ -35,7 +35,7 @@ pub use self::font::{FontFamily, FontLanguageOverride, FontVariantSettings, Font
 pub use self::font::{FontVariantLigatures, FontVariantNumeric, FontFeatureSettings};
 pub use self::font::{MozScriptLevel, MozScriptMinSize, MozScriptSizeMultiplier, XTextZoom, XLang};
 pub use self::box_::{AnimationIterationCount, AnimationName, OverscrollBehavior};
-pub use self::box_::{OverflowClipBox, ScrollSnapType, VerticalAlign};
+pub use self::box_::{OverflowClipBox, ScrollSnapType, VerticalAlign, WillChange};
 pub use self::color::{Color, ColorPropertyValue, RGBAColor};
 pub use self::effects::{BoxShadow, Filter, SimpleShadow};
 pub use self::flex::FlexBasis;
@ -49,6 +49,8 @@ pub use self::length::{LengthOrPercentage, LengthOrPercentageOrAuto};
 pub use self::length::{LengthOrPercentageOrNone, MaxLength, MozLength};
 pub use self::length::{NoCalcLength, ViewportPercentageLength};
 pub use self::length::NonNegativeLengthOrPercentage;
 pub use self::list::{ListStyleImage, Quotes};
 pub use self::outline::OutlineStyle;
 pub use self::rect::LengthOrNumberRect;
 pub use self::percentage::Percentage;
 pub use self::position::{Position, PositionComponent, GridAutoFlow, GridTemplateAreas};
@ -78,6 +80,8 @@ pub mod gecko;
 pub mod grid;
 pub mod image;
 pub mod length;
 pub mod list;
 pub mod outline;
 pub mod percentage;
 pub mod position;
 pub mod rect;
--- a/components/style/values/specified/outline.rs
+++ b/components/style/values/specified/outline.rs
@ -0,0 +1,56 @@
 /* This Source Code Form is subject to the terms of the Mozilla Public
 * License, v. 2.0. If a copy of the MPL was not distributed with this
 * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
 //! Specified values for outline properties
 use cssparser::Parser;
 use parser::{Parse, ParserContext};
 use selectors::parser::SelectorParseErrorKind;
 use style_traits::ParseError;
 use values::specified::BorderStyle;
 #[derive(Clone, Copy, Debug, Eq, MallocSizeOf, Ord)]
 #[derive(PartialEq, PartialOrd, ToComputedValue, ToCss)]
 /// <https://drafts.csswg.org/css-ui/#propdef-outline-style>
 pub enum OutlineStyle {
    /// auto
    Auto,
    /// <border-style>
    Other(BorderStyle),
 }
 impl OutlineStyle {
    #[inline]
    /// Get default value as None
    pub fn none() -> OutlineStyle {
        OutlineStyle::Other(BorderStyle::None)
    }
    #[inline]
    /// Get value for None or Hidden
    pub fn none_or_hidden(&self) -> bool {
        match *self {
            OutlineStyle::Auto => false,
            OutlineStyle::Other(ref border_style) => border_style.none_or_hidden()
        }
    }
 }
 impl Parse for OutlineStyle {
    fn parse<'i, 't>(
        context: &ParserContext,
        input: &mut Parser<'i, 't>
    ) -> Result<OutlineStyle, ParseError<'i>> {
        if let Ok(border_style) = input.try(|i| BorderStyle::parse(context, i)) {
            if let BorderStyle::Hidden = border_style {
                return Err(input.new_custom_error(SelectorParseErrorKind::UnexpectedIdent("hidden".into())));
            }
            return Ok(OutlineStyle::Other(border_style));
        }
        input.expect_ident_matching("auto")?;
        Ok(OutlineStyle::Auto)
    }
 }
--- a/components/style/values/specified/position.rs
+++ b/components/style/values/specified/position.rs
@ -42,17 +42,21 @@ pub enum PositionComponent<S> {
    Side(S, Option<LengthOrPercentage>),
 }
-define_css_keyword_enum! { X:
+/// A keyword for the X direction.
-    "left" => Left,
+#[derive(Clone, Copy, Debug, Eq, Hash, MallocSizeOf, Parse, PartialEq, ToComputedValue, ToCss)]
-    "right" => Right,
+#[allow(missing_docs)]
 pub enum X {
    Left,
    Right,
 }
 add_impls_for_keyword_enum!(X);
-define_css_keyword_enum! { Y:
+/// A keyword for the Y direction.
-    "top" => Top,
+#[derive(Clone, Copy, Debug, Eq, Hash, MallocSizeOf, Parse, PartialEq, ToComputedValue, ToCss)]
-    "bottom" => Bottom,
+#[allow(missing_docs)]
 pub enum Y {
    Top,
    Bottom,
 }
 add_impls_for_keyword_enum!(Y);
 impl Parse for Position {
    fn parse<'i, 't>(context: &ParserContext, input: &mut Parser<'i, 't>) -> Result<Self, ParseError<'i>> {
--- a/components/style_derive/cg.rs
+++ b/components/style_derive/cg.rs
@ -406,3 +406,41 @@ pub fn where_predicate(
        )],
    })
 }
 /// Transforms "FooBar" to "foo-bar".
 ///
 /// If the first Camel segment is "Moz", "Webkit", or "Servo", the result string
 /// is prepended with "-".
 pub fn to_css_identifier(mut camel_case: &str) -> String {
    camel_case = camel_case.trim_right_matches('_');
    let mut first = true;
    let mut result = String::with_capacity(camel_case.len());
    while let Some(segment) = split_camel_segment(&mut camel_case) {
        if first {
            match segment {
                "Moz" | "Webkit" | "Servo" => first = false,
                _ => {},
            }
        }
        if !first {
            result.push_str("-");
        }
        first = false;
        result.push_str(&segment.to_lowercase());
    }
    result
 }
 /// Given "FooBar", returns "Foo" and sets `camel_case` to "Bar".
 fn split_camel_segment<'input>(camel_case: &mut &'input str) -> Option<&'input str> {
    let index = match camel_case.chars().next() {
        None => return None,
        Some(ch) => ch.len_utf8(),
    };
    let end_position = camel_case[index..]
        .find(char::is_uppercase)
        .map_or(camel_case.len(), |pos| index + pos);
    let result = &camel_case[..end_position];
    *camel_case = &camel_case[end_position..];
    Some(result)
 }
--- a/components/style_derive/lib.rs
+++ b/components/style_derive/lib.rs
@ -2,6 +2,8 @@
 * License, v. 2.0. If a copy of the MPL was not distributed with this
 * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
 #![recursion_limit = "128"]
 #[macro_use] extern crate darling;
 extern crate proc_macro;
 #[macro_use] extern crate quote;
@ -13,6 +15,7 @@ use proc_macro::TokenStream;
 mod animate;
 mod cg;
 mod compute_squared_distance;
 mod parse;
 mod to_animated_value;
 mod to_animated_zero;
 mod to_computed_value;
@ -36,6 +39,12 @@ pub fn derive_to_animated_value(stream: TokenStream) -> TokenStream {
    to_animated_value::derive(input).to_string().parse().unwrap()
 }
 #[proc_macro_derive(Parse)]
 pub fn derive_parse(stream: TokenStream) -> TokenStream {
    let input = syn::parse_derive_input(&stream.to_string()).unwrap();
    parse::derive(input).to_string().parse().unwrap()
 }
 #[proc_macro_derive(ToAnimatedZero, attributes(animation))]
 pub fn derive_to_animated_zero(stream: TokenStream) -> TokenStream {
    let input = syn::parse_derive_input(&stream.to_string()).unwrap();
--- a/components/style_derive/parse.rs
+++ b/components/style_derive/parse.rs
@ -0,0 +1,74 @@
 /* This Source Code Form is subject to the terms of the Mozilla Public
 * License, v. 2.0. If a copy of the MPL was not distributed with this
 * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
 use cg;
 use quote::Tokens;
 use syn::DeriveInput;
 use synstructure;
 pub fn derive(input: DeriveInput) -> Tokens {
    let name = &input.ident;
    let mut match_body = quote! {};
    let style = synstructure::BindStyle::Ref.into();
    synstructure::each_variant(&input, &style, |bindings, variant| {
        assert!(
            bindings.is_empty(),
            "Parse is only supported for single-variant enums for now"
        );
        let identifier = cg::to_css_identifier(variant.ident.as_ref());
        match_body = quote! {
            #match_body
            #identifier => Ok(#name::#variant),
        }
    });
    let parse_trait_impl = quote! {
        impl ::parser::Parse for #name {
            #[inline]
            fn parse<'i, 't>(
                _: &::parser::ParserContext,
                input: &mut ::cssparser::Parser<'i, 't>,
            ) -> Result<Self, ::style_traits::ParseError<'i>> {
                Self::parse(input)
            }
        }
    };
    // TODO(emilio): It'd be nice to get rid of these, but that makes the
    // conversion harder...
    let methods_impl = quote! {
        impl #name {
            /// Parse this keyword.
            #[inline]
            pub fn parse<'i, 't>(
                input: &mut ::cssparser::Parser<'i, 't>,
            ) -> Result<Self, ::style_traits::ParseError<'i>> {
                let location = input.current_source_location();
                let ident = input.expect_ident()?;
                Self::from_ident(ident.as_ref()).map_err(|()| {
                    location.new_unexpected_token_error(
                        ::cssparser::Token::Ident(ident.clone())
                    )
                })
            }
            /// Parse this keyword from a string slice.
            #[inline]
            pub fn from_ident(ident: &str) -> Result<Self, ()> {
                match_ignore_ascii_case! { ident,
                    #match_body
                    _ => Err(()),
                }
            }
        }
    };
    quote! {
        #parse_trait_impl
        #methods_impl
    }
 }
--- a/components/style_derive/to_css.rs
+++ b/components/style_derive/to_css.rs
@ -16,7 +16,7 @@ pub fn derive(input: DeriveInput) -> Tokens {
    let input_attrs = cg::parse_input_attrs::<CssInputAttrs>(&input);
    let style = synstructure::BindStyle::Ref.into();
    let match_body = synstructure::each_variant(&input, &style, |bindings, variant| {
-        let mut identifier = to_css_identifier(variant.ident.as_ref());
+        let mut identifier = cg::to_css_identifier(variant.ident.as_ref());
        let variant_attrs = cg::parse_variant_attrs::<CssVariantAttrs>(variant);
        let separator = if variant_attrs.comma { ", " } else { " " };
@ -27,7 +27,7 @@ pub fn derive(input: DeriveInput) -> Tokens {
        let mut expr = if !bindings.is_empty() {
            let mut expr = quote! {};
-            if variant_attrs.function && variant_attrs.iterable {
+            if variant_attrs.iterable {
                assert_eq!(bindings.len(), 1);
                let binding = &bindings[0];
                expr = quote! {
@ -118,41 +118,3 @@ struct CssVariantAttrs {
    comma: bool,
    dimension: bool,
 }
 /// Transforms "FooBar" to "foo-bar".
 ///
 /// If the first Camel segment is "Moz" or "Webkit", the result string
 /// is prepended with "-".
 fn to_css_identifier(mut camel_case: &str) -> String {
    camel_case = camel_case.trim_right_matches('_');
    let mut first = true;
    let mut result = String::with_capacity(camel_case.len());
    while let Some(segment) = split_camel_segment(&mut camel_case) {
        if first {
            match segment {
                "Moz" | "Webkit" => first = false,
                _ => {},
            }
        }
        if !first {
            result.push_str("-");
        }
        first = false;
        result.push_str(&segment.to_lowercase());
    }
    result
 }
 /// Given "FooBar", returns "Foo" and sets `camel_case` to "Bar".
 fn split_camel_segment<'input>(camel_case: &mut &'input str) -> Option<&'input str> {
    let index = match camel_case.chars().next() {
        None => return None,
        Some(ch) => ch.len_utf8(),
    };
    let end_position = camel_case[index..]
        .find(char::is_uppercase)
        .map_or(camel_case.len(), |pos| index + pos);
    let result = &camel_case[..end_position];
    *camel_case = &camel_case[end_position..];
    Some(result)
 }
--- a/Show more
+++ b/Show more