diff --git a/Cargo.lock b/Cargo.lock
index d9da141d72e..ad21fbedaf4 100644
--- a/Cargo.lock
+++ b/Cargo.lock
@@ -132,7 +132,7 @@ dependencies = [
 
 [[package]]
 name = "autocfg"
-version = "0.1.2"
+version = "0.1.4"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 
 [[package]]
@@ -171,7 +171,7 @@ name = "backtrace"
 version = "0.3.26"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 dependencies = [
- "autocfg 0.1.2 (registry+https://github.com/rust-lang/crates.io-index)",
+ "autocfg 0.1.4 (registry+https://github.com/rust-lang/crates.io-index)",
  "backtrace-sys 0.1.24 (registry+https://github.com/rust-lang/crates.io-index)",
  "cfg-if 0.1.6 (registry+https://github.com/rust-lang/crates.io-index)",
  "libc 0.2.53 (registry+https://github.com/rust-lang/crates.io-index)",
@@ -394,7 +394,7 @@ dependencies = [
  "azure 0.36.0 (git+https://github.com/servo/rust-azure)",
  "byteorder 1.2.7 (registry+https://github.com/rust-lang/crates.io-index)",
  "canvas_traits 0.0.1",
- "cssparser 0.25.7 (registry+https://github.com/rust-lang/crates.io-index)",
+ "cssparser 0.25.8 (registry+https://github.com/rust-lang/crates.io-index)",
  "euclid 0.19.8 (registry+https://github.com/rust-lang/crates.io-index)",
  "fnv 1.0.6 (registry+https://github.com/rust-lang/crates.io-index)",
  "gleam 0.6.18 (registry+https://github.com/rust-lang/crates.io-index)",
@@ -416,7 +416,7 @@ dependencies = [
 name = "canvas_traits"
 version = "0.0.1"
 dependencies = [
- "cssparser 0.25.7 (registry+https://github.com/rust-lang/crates.io-index)",
+ "cssparser 0.25.8 (registry+https://github.com/rust-lang/crates.io-index)",
  "euclid 0.19.8 (registry+https://github.com/rust-lang/crates.io-index)",
  "gleam 0.6.18 (registry+https://github.com/rust-lang/crates.io-index)",
  "ipc-channel 0.11.3 (registry+https://github.com/rust-lang/crates.io-index)",
@@ -452,7 +452,7 @@ dependencies = [
  "serde 1.0.88 (registry+https://github.com/rust-lang/crates.io-index)",
  "serde_derive 1.0.88 (registry+https://github.com/rust-lang/crates.io-index)",
  "serde_json 1.0.13 (registry+https://github.com/rust-lang/crates.io-index)",
- "syn 0.15.34 (registry+https://github.com/rust-lang/crates.io-index)",
+ "syn 0.15.39 (registry+https://github.com/rust-lang/crates.io-index)",
  "tempfile 3.0.8 (registry+https://github.com/rust-lang/crates.io-index)",
  "toml 0.4.5 (registry+https://github.com/rust-lang/crates.io-index)",
 ]
@@ -812,9 +812,10 @@ dependencies = [
 
 [[package]]
 name = "cssparser"
-version = "0.25.7"
+version = "0.25.8"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 dependencies = [
+ "autocfg 0.1.4 (registry+https://github.com/rust-lang/crates.io-index)",
  "cssparser-macros 0.3.5 (registry+https://github.com/rust-lang/crates.io-index)",
  "dtoa-short 0.3.0 (registry+https://github.com/rust-lang/crates.io-index)",
  "itoa 0.4.1 (registry+https://github.com/rust-lang/crates.io-index)",
@@ -825,7 +826,7 @@ dependencies = [
  "quote 0.6.12 (registry+https://github.com/rust-lang/crates.io-index)",
  "serde 1.0.88 (registry+https://github.com/rust-lang/crates.io-index)",
  "smallvec 0.6.7 (registry+https://github.com/rust-lang/crates.io-index)",
- "syn 0.15.34 (registry+https://github.com/rust-lang/crates.io-index)",
+ "syn 0.15.39 (registry+https://github.com/rust-lang/crates.io-index)",
 ]
 
 [[package]]
@@ -837,7 +838,7 @@ dependencies = [
  "proc-macro2 0.4.26 (registry+https://github.com/rust-lang/crates.io-index)",
  "procedural-masquerade 0.1.6 (registry+https://github.com/rust-lang/crates.io-index)",
  "quote 0.6.12 (registry+https://github.com/rust-lang/crates.io-index)",
- "syn 0.15.34 (registry+https://github.com/rust-lang/crates.io-index)",
+ "syn 0.15.39 (registry+https://github.com/rust-lang/crates.io-index)",
 ]
 
 [[package]]
@@ -855,7 +856,7 @@ version = "0.1.5"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 dependencies = [
  "procedural-masquerade 0.1.6 (registry+https://github.com/rust-lang/crates.io-index)",
- "syn 0.15.34 (registry+https://github.com/rust-lang/crates.io-index)",
+ "syn 0.15.39 (registry+https://github.com/rust-lang/crates.io-index)",
 ]
 
 [[package]]
@@ -864,7 +865,7 @@ version = "0.1.9"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 dependencies = [
  "quote 0.6.12 (registry+https://github.com/rust-lang/crates.io-index)",
- "syn 0.15.34 (registry+https://github.com/rust-lang/crates.io-index)",
+ "syn 0.15.39 (registry+https://github.com/rust-lang/crates.io-index)",
 ]
 
 [[package]]
@@ -886,7 +887,7 @@ dependencies = [
  "proc-macro2 0.4.26 (registry+https://github.com/rust-lang/crates.io-index)",
  "quote 0.6.12 (registry+https://github.com/rust-lang/crates.io-index)",
  "strsim 0.7.0 (registry+https://github.com/rust-lang/crates.io-index)",
- "syn 0.15.34 (registry+https://github.com/rust-lang/crates.io-index)",
+ "syn 0.15.39 (registry+https://github.com/rust-lang/crates.io-index)",
 ]
 
 [[package]]
@@ -896,7 +897,7 @@ source = "registry+https://github.com/rust-lang/crates.io-index"
 dependencies = [
  "darling_core 0.9.0 (registry+https://github.com/rust-lang/crates.io-index)",
  "quote 0.6.12 (registry+https://github.com/rust-lang/crates.io-index)",
- "syn 0.15.34 (registry+https://github.com/rust-lang/crates.io-index)",
+ "syn 0.15.39 (registry+https://github.com/rust-lang/crates.io-index)",
 ]
 
 [[package]]
@@ -930,7 +931,7 @@ dependencies = [
 name = "deny_public_fields"
 version = "0.0.1"
 dependencies = [
- "syn 0.15.34 (registry+https://github.com/rust-lang/crates.io-index)",
+ "syn 0.15.39 (registry+https://github.com/rust-lang/crates.io-index)",
  "synstructure 0.10.1 (registry+https://github.com/rust-lang/crates.io-index)",
 ]
 
@@ -948,7 +949,7 @@ source = "registry+https://github.com/rust-lang/crates.io-index"
 dependencies = [
  "proc-macro2 0.4.26 (registry+https://github.com/rust-lang/crates.io-index)",
  "quote 0.6.12 (registry+https://github.com/rust-lang/crates.io-index)",
- "syn 0.15.34 (registry+https://github.com/rust-lang/crates.io-index)",
+ "syn 0.15.39 (registry+https://github.com/rust-lang/crates.io-index)",
 ]
 
 [[package]]
@@ -958,7 +959,7 @@ dependencies = [
  "darling 0.9.0 (registry+https://github.com/rust-lang/crates.io-index)",
  "proc-macro2 0.4.26 (registry+https://github.com/rust-lang/crates.io-index)",
  "quote 0.6.12 (registry+https://github.com/rust-lang/crates.io-index)",
- "syn 0.15.34 (registry+https://github.com/rust-lang/crates.io-index)",
+ "syn 0.15.39 (registry+https://github.com/rust-lang/crates.io-index)",
  "synstructure 0.10.1 (registry+https://github.com/rust-lang/crates.io-index)",
 ]
 
@@ -970,7 +971,7 @@ dependencies = [
  "proc-macro2 0.4.26 (registry+https://github.com/rust-lang/crates.io-index)",
  "quote 0.6.12 (registry+https://github.com/rust-lang/crates.io-index)",
  "rustc_version 0.2.3 (registry+https://github.com/rust-lang/crates.io-index)",
- "syn 0.15.34 (registry+https://github.com/rust-lang/crates.io-index)",
+ "syn 0.15.39 (registry+https://github.com/rust-lang/crates.io-index)",
 ]
 
 [[package]]
@@ -1049,7 +1050,7 @@ name = "dom_struct"
 version = "0.0.1"
 dependencies = [
  "quote 0.6.12 (registry+https://github.com/rust-lang/crates.io-index)",
- "syn 0.15.34 (registry+https://github.com/rust-lang/crates.io-index)",
+ "syn 0.15.39 (registry+https://github.com/rust-lang/crates.io-index)",
 ]
 
 [[package]]
@@ -1058,7 +1059,7 @@ version = "0.0.1"
 dependencies = [
  "proc-macro2 0.4.26 (registry+https://github.com/rust-lang/crates.io-index)",
  "quote 0.6.12 (registry+https://github.com/rust-lang/crates.io-index)",
- "syn 0.15.34 (registry+https://github.com/rust-lang/crates.io-index)",
+ "syn 0.15.39 (registry+https://github.com/rust-lang/crates.io-index)",
 ]
 
 [[package]]
@@ -1179,7 +1180,7 @@ source = "registry+https://github.com/rust-lang/crates.io-index"
 dependencies = [
  "proc-macro2 0.4.26 (registry+https://github.com/rust-lang/crates.io-index)",
  "quote 0.6.12 (registry+https://github.com/rust-lang/crates.io-index)",
- "syn 0.15.34 (registry+https://github.com/rust-lang/crates.io-index)",
+ "syn 0.15.39 (registry+https://github.com/rust-lang/crates.io-index)",
 ]
 
 [[package]]
@@ -1227,7 +1228,7 @@ source = "registry+https://github.com/rust-lang/crates.io-index"
 dependencies = [
  "proc-macro2 0.4.26 (registry+https://github.com/rust-lang/crates.io-index)",
  "quote 0.6.12 (registry+https://github.com/rust-lang/crates.io-index)",
- "syn 0.15.34 (registry+https://github.com/rust-lang/crates.io-index)",
+ "syn 0.15.39 (registry+https://github.com/rust-lang/crates.io-index)",
 ]
 
 [[package]]
@@ -1475,7 +1476,7 @@ source = "registry+https://github.com/rust-lang/crates.io-index"
 dependencies = [
  "proc-macro2 0.4.26 (registry+https://github.com/rust-lang/crates.io-index)",
  "quote 0.6.12 (registry+https://github.com/rust-lang/crates.io-index)",
- "syn 0.15.34 (registry+https://github.com/rust-lang/crates.io-index)",
+ "syn 0.15.39 (registry+https://github.com/rust-lang/crates.io-index)",
 ]
 
 [[package]]
@@ -1975,7 +1976,7 @@ source = "registry+https://github.com/rust-lang/crates.io-index"
 dependencies = [
  "proc-macro2 0.4.26 (registry+https://github.com/rust-lang/crates.io-index)",
  "quote 0.6.12 (registry+https://github.com/rust-lang/crates.io-index)",
- "syn 0.15.34 (registry+https://github.com/rust-lang/crates.io-index)",
+ "syn 0.15.39 (registry+https://github.com/rust-lang/crates.io-index)",
 ]
 
 [[package]]
@@ -2017,7 +2018,7 @@ dependencies = [
  "markup5ever 0.8.1 (registry+https://github.com/rust-lang/crates.io-index)",
  "proc-macro2 0.4.26 (registry+https://github.com/rust-lang/crates.io-index)",
  "quote 0.6.12 (registry+https://github.com/rust-lang/crates.io-index)",
- "syn 0.15.34 (registry+https://github.com/rust-lang/crates.io-index)",
+ "syn 0.15.39 (registry+https://github.com/rust-lang/crates.io-index)",
 ]
 
 [[package]]
@@ -2188,7 +2189,7 @@ source = "registry+https://github.com/rust-lang/crates.io-index"
 dependencies = [
  "proc-macro2 0.4.26 (registry+https://github.com/rust-lang/crates.io-index)",
  "quote 0.6.12 (registry+https://github.com/rust-lang/crates.io-index)",
- "syn 0.15.34 (registry+https://github.com/rust-lang/crates.io-index)",
+ "syn 0.15.39 (registry+https://github.com/rust-lang/crates.io-index)",
 ]
 
 [[package]]
@@ -2283,7 +2284,7 @@ name = "jstraceable_derive"
 version = "0.0.1"
 dependencies = [
  "proc-macro2 0.4.26 (registry+https://github.com/rust-lang/crates.io-index)",
- "syn 0.15.34 (registry+https://github.com/rust-lang/crates.io-index)",
+ "syn 0.15.39 (registry+https://github.com/rust-lang/crates.io-index)",
  "synstructure 0.10.1 (registry+https://github.com/rust-lang/crates.io-index)",
 ]
 
@@ -2671,7 +2672,7 @@ version = "0.0.1"
 dependencies = [
  "app_units 0.7.0 (registry+https://github.com/rust-lang/crates.io-index)",
  "crossbeam-channel 0.3.8 (registry+https://github.com/rust-lang/crates.io-index)",
- "cssparser 0.25.7 (registry+https://github.com/rust-lang/crates.io-index)",
+ "cssparser 0.25.8 (registry+https://github.com/rust-lang/crates.io-index)",
  "euclid 0.19.8 (registry+https://github.com/rust-lang/crates.io-index)",
  "hashglobe 0.1.0",
  "hyper 0.12.14 (registry+https://github.com/rust-lang/crates.io-index)",
@@ -2698,7 +2699,7 @@ version = "0.1.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 dependencies = [
  "proc-macro2 0.4.26 (registry+https://github.com/rust-lang/crates.io-index)",
- "syn 0.15.34 (registry+https://github.com/rust-lang/crates.io-index)",
+ "syn 0.15.39 (registry+https://github.com/rust-lang/crates.io-index)",
  "synstructure 0.10.1 (registry+https://github.com/rust-lang/crates.io-index)",
 ]
 
@@ -3115,7 +3116,7 @@ dependencies = [
  "num-traits 0.2.4 (registry+https://github.com/rust-lang/crates.io-index)",
  "proc-macro2 0.4.26 (registry+https://github.com/rust-lang/crates.io-index)",
  "quote 0.6.12 (registry+https://github.com/rust-lang/crates.io-index)",
- "syn 0.15.34 (registry+https://github.com/rust-lang/crates.io-index)",
+ "syn 0.15.39 (registry+https://github.com/rust-lang/crates.io-index)",
 ]
 
 [[package]]
@@ -3343,7 +3344,7 @@ dependencies = [
  "proc-macro-hack 0.5.7 (registry+https://github.com/rust-lang/crates.io-index)",
  "proc-macro2 0.4.26 (registry+https://github.com/rust-lang/crates.io-index)",
  "quote 0.6.12 (registry+https://github.com/rust-lang/crates.io-index)",
- "syn 0.15.34 (registry+https://github.com/rust-lang/crates.io-index)",
+ "syn 0.15.39 (registry+https://github.com/rust-lang/crates.io-index)",
 ]
 
 [[package]]
@@ -3454,7 +3455,7 @@ source = "registry+https://github.com/rust-lang/crates.io-index"
 dependencies = [
  "proc-macro2 0.4.26 (registry+https://github.com/rust-lang/crates.io-index)",
  "quote 0.6.12 (registry+https://github.com/rust-lang/crates.io-index)",
- "syn 0.15.34 (registry+https://github.com/rust-lang/crates.io-index)",
+ "syn 0.15.39 (registry+https://github.com/rust-lang/crates.io-index)",
 ]
 
 [[package]]
@@ -3546,7 +3547,7 @@ name = "rand"
 version = "0.6.5"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 dependencies = [
- "autocfg 0.1.2 (registry+https://github.com/rust-lang/crates.io-index)",
+ "autocfg 0.1.4 (registry+https://github.com/rust-lang/crates.io-index)",
  "libc 0.2.53 (registry+https://github.com/rust-lang/crates.io-index)",
  "rand_chacha 0.1.1 (registry+https://github.com/rust-lang/crates.io-index)",
  "rand_core 0.4.0 (registry+https://github.com/rust-lang/crates.io-index)",
@@ -3564,7 +3565,7 @@ name = "rand_chacha"
 version = "0.1.1"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 dependencies = [
- "autocfg 0.1.2 (registry+https://github.com/rust-lang/crates.io-index)",
+ "autocfg 0.1.4 (registry+https://github.com/rust-lang/crates.io-index)",
  "rand_core 0.3.1 (registry+https://github.com/rust-lang/crates.io-index)",
 ]
 
@@ -3625,7 +3626,7 @@ name = "rand_pcg"
 version = "0.1.2"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 dependencies = [
- "autocfg 0.1.2 (registry+https://github.com/rust-lang/crates.io-index)",
+ "autocfg 0.1.4 (registry+https://github.com/rust-lang/crates.io-index)",
  "rand_core 0.4.0 (registry+https://github.com/rust-lang/crates.io-index)",
 ]
 
@@ -3846,7 +3847,7 @@ dependencies = [
  "cmake 0.1.40 (git+https://github.com/alexcrichton/cmake-rs)",
  "cookie 0.11.0 (registry+https://github.com/rust-lang/crates.io-index)",
  "crossbeam-channel 0.3.8 (registry+https://github.com/rust-lang/crates.io-index)",
- "cssparser 0.25.7 (registry+https://github.com/rust-lang/crates.io-index)",
+ "cssparser 0.25.8 (registry+https://github.com/rust-lang/crates.io-index)",
  "deny_public_fields 0.0.1",
  "devtools_traits 0.0.1",
  "dom_struct 0.0.1",
@@ -3933,7 +3934,7 @@ dependencies = [
  "atomic_refcell 0.1.0 (registry+https://github.com/rust-lang/crates.io-index)",
  "canvas_traits 0.0.1",
  "crossbeam-channel 0.3.8 (registry+https://github.com/rust-lang/crates.io-index)",
- "cssparser 0.25.7 (registry+https://github.com/rust-lang/crates.io-index)",
+ "cssparser 0.25.8 (registry+https://github.com/rust-lang/crates.io-index)",
  "euclid 0.19.8 (registry+https://github.com/rust-lang/crates.io-index)",
  "gfx_traits 0.0.1",
  "html5ever 0.23.0 (registry+https://github.com/rust-lang/crates.io-index)",
@@ -4021,7 +4022,7 @@ name = "selectors"
 version = "0.21.0"
 dependencies = [
  "bitflags 1.0.3 (registry+https://github.com/rust-lang/crates.io-index)",
- "cssparser 0.25.7 (registry+https://github.com/rust-lang/crates.io-index)",
+ "cssparser 0.25.8 (registry+https://github.com/rust-lang/crates.io-index)",
  "derive_more 0.13.0 (registry+https://github.com/rust-lang/crates.io-index)",
  "fxhash 0.2.1 (registry+https://github.com/rust-lang/crates.io-index)",
  "log 0.4.6 (registry+https://github.com/rust-lang/crates.io-index)",
@@ -4072,7 +4073,7 @@ source = "registry+https://github.com/rust-lang/crates.io-index"
 dependencies = [
  "proc-macro2 0.4.26 (registry+https://github.com/rust-lang/crates.io-index)",
  "quote 0.6.12 (registry+https://github.com/rust-lang/crates.io-index)",
- "syn 0.15.34 (registry+https://github.com/rust-lang/crates.io-index)",
+ "syn 0.15.39 (registry+https://github.com/rust-lang/crates.io-index)",
 ]
 
 [[package]]
@@ -4365,7 +4366,7 @@ dependencies = [
  "itertools 0.8.0 (registry+https://github.com/rust-lang/crates.io-index)",
  "proc-macro2 0.4.26 (registry+https://github.com/rust-lang/crates.io-index)",
  "quote 0.6.12 (registry+https://github.com/rust-lang/crates.io-index)",
- "syn 0.15.34 (registry+https://github.com/rust-lang/crates.io-index)",
+ "syn 0.15.39 (registry+https://github.com/rust-lang/crates.io-index)",
 ]
 
 [[package]]
@@ -4387,7 +4388,7 @@ source = "git+https://github.com/servo/media#ae9d071e72cef4bbf1aaf54004007c7047b
 dependencies = [
  "proc-macro2 0.4.26 (registry+https://github.com/rust-lang/crates.io-index)",
  "quote 0.6.12 (registry+https://github.com/rust-lang/crates.io-index)",
- "syn 0.15.34 (registry+https://github.com/rust-lang/crates.io-index)",
+ "syn 0.15.39 (registry+https://github.com/rust-lang/crates.io-index)",
 ]
 
 [[package]]
@@ -4636,7 +4637,7 @@ dependencies = [
  "bitflags 1.0.3 (registry+https://github.com/rust-lang/crates.io-index)",
  "byteorder 1.2.7 (registry+https://github.com/rust-lang/crates.io-index)",
  "crossbeam-channel 0.3.8 (registry+https://github.com/rust-lang/crates.io-index)",
- "cssparser 0.25.7 (registry+https://github.com/rust-lang/crates.io-index)",
+ "cssparser 0.25.8 (registry+https://github.com/rust-lang/crates.io-index)",
  "derive_more 0.13.0 (registry+https://github.com/rust-lang/crates.io-index)",
  "encoding_rs 0.8.12 (registry+https://github.com/rust-lang/crates.io-index)",
  "euclid 0.19.8 (registry+https://github.com/rust-lang/crates.io-index)",
@@ -4694,7 +4695,7 @@ dependencies = [
  "derive_common 0.0.1",
  "proc-macro2 0.4.26 (registry+https://github.com/rust-lang/crates.io-index)",
  "quote 0.6.12 (registry+https://github.com/rust-lang/crates.io-index)",
- "syn 0.15.34 (registry+https://github.com/rust-lang/crates.io-index)",
+ "syn 0.15.39 (registry+https://github.com/rust-lang/crates.io-index)",
  "synstructure 0.10.1 (registry+https://github.com/rust-lang/crates.io-index)",
 ]
 
@@ -4704,7 +4705,7 @@ version = "0.0.1"
 dependencies = [
  "app_units 0.7.0 (registry+https://github.com/rust-lang/crates.io-index)",
  "byteorder 1.2.7 (registry+https://github.com/rust-lang/crates.io-index)",
- "cssparser 0.25.7 (registry+https://github.com/rust-lang/crates.io-index)",
+ "cssparser 0.25.8 (registry+https://github.com/rust-lang/crates.io-index)",
  "euclid 0.19.8 (registry+https://github.com/rust-lang/crates.io-index)",
  "html5ever 0.23.0 (registry+https://github.com/rust-lang/crates.io-index)",
  "rayon 1.0.0 (registry+https://github.com/rust-lang/crates.io-index)",
@@ -4726,7 +4727,7 @@ version = "0.0.1"
 dependencies = [
  "app_units 0.7.0 (registry+https://github.com/rust-lang/crates.io-index)",
  "bitflags 1.0.3 (registry+https://github.com/rust-lang/crates.io-index)",
- "cssparser 0.25.7 (registry+https://github.com/rust-lang/crates.io-index)",
+ "cssparser 0.25.8 (registry+https://github.com/rust-lang/crates.io-index)",
  "euclid 0.19.8 (registry+https://github.com/rust-lang/crates.io-index)",
  "lazy_static 1.3.0 (registry+https://github.com/rust-lang/crates.io-index)",
  "malloc_size_of 0.0.1",
@@ -4758,7 +4759,7 @@ source = "registry+https://github.com/rust-lang/crates.io-index"
 
 [[package]]
 name = "syn"
-version = "0.15.34"
+version = "0.15.39"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 dependencies = [
  "proc-macro2 0.4.26 (registry+https://github.com/rust-lang/crates.io-index)",
@@ -4773,7 +4774,7 @@ source = "registry+https://github.com/rust-lang/crates.io-index"
 dependencies = [
  "proc-macro2 0.4.26 (registry+https://github.com/rust-lang/crates.io-index)",
  "quote 0.6.12 (registry+https://github.com/rust-lang/crates.io-index)",
- "syn 0.15.34 (registry+https://github.com/rust-lang/crates.io-index)",
+ "syn 0.15.39 (registry+https://github.com/rust-lang/crates.io-index)",
  "unicode-xid 0.1.0 (registry+https://github.com/rust-lang/crates.io-index)",
 ]
 
@@ -4891,7 +4892,7 @@ dependencies = [
 name = "to_shmem"
 version = "0.0.1"
 dependencies = [
- "cssparser 0.25.7 (registry+https://github.com/rust-lang/crates.io-index)",
+ "cssparser 0.25.8 (registry+https://github.com/rust-lang/crates.io-index)",
  "serde 1.0.88 (registry+https://github.com/rust-lang/crates.io-index)",
  "servo_arc 0.1.1",
  "smallbitvec 2.3.0 (registry+https://github.com/rust-lang/crates.io-index)",
@@ -4908,7 +4909,7 @@ dependencies = [
  "derive_common 0.0.1",
  "proc-macro2 0.4.26 (registry+https://github.com/rust-lang/crates.io-index)",
  "quote 0.6.12 (registry+https://github.com/rust-lang/crates.io-index)",
- "syn 0.15.34 (registry+https://github.com/rust-lang/crates.io-index)",
+ "syn 0.15.39 (registry+https://github.com/rust-lang/crates.io-index)",
  "synstructure 0.10.1 (registry+https://github.com/rust-lang/crates.io-index)",
 ]
 
@@ -5120,7 +5121,7 @@ source = "registry+https://github.com/rust-lang/crates.io-index"
 dependencies = [
  "proc-macro2 0.4.26 (registry+https://github.com/rust-lang/crates.io-index)",
  "quote 0.6.12 (registry+https://github.com/rust-lang/crates.io-index)",
- "syn 0.15.34 (registry+https://github.com/rust-lang/crates.io-index)",
+ "syn 0.15.39 (registry+https://github.com/rust-lang/crates.io-index)",
 ]
 
 [[package]]
@@ -5728,7 +5729,7 @@ dependencies = [
 "checksum ascii 0.7.1 (registry+https://github.com/rust-lang/crates.io-index)" = "3ae7d751998c189c1d4468cf0a39bb2eae052a9c58d50ebb3b9591ee3813ad50"
 "checksum atomic_refcell 0.1.0 (registry+https://github.com/rust-lang/crates.io-index)" = "fb2dcb6e6d35f20276943cc04bb98e538b348d525a04ac79c10021561d202f21"
 "checksum atty 0.2.11 (registry+https://github.com/rust-lang/crates.io-index)" = "9a7d5b8723950951411ee34d271d99dddcc2035a16ab25310ea2c8cfd4369652"
-"checksum autocfg 0.1.2 (registry+https://github.com/rust-lang/crates.io-index)" = "a6d640bee2da49f60a4068a7fae53acde8982514ab7bae8b8cea9e88cbcfd799"
+"checksum autocfg 0.1.4 (registry+https://github.com/rust-lang/crates.io-index)" = "0e49efa51329a5fd37e7c79db4621af617cd4e3e5bc224939808d076077077bf"
 "checksum azure 0.36.0 (git+https://github.com/servo/rust-azure)" = "<none>"
 "checksum backtrace 0.3.26 (registry+https://github.com/rust-lang/crates.io-index)" = "1a13fc43f04daf08ab4f71e3d27e1fc27fc437d3e95ac0063a796d92fb40f39b"
 "checksum backtrace-sys 0.1.24 (registry+https://github.com/rust-lang/crates.io-index)" = "c66d56ac8dabd07f6aacdaf633f4b8262f5b3601a810a0dcddffd5c22c69daa0"
@@ -5787,7 +5788,7 @@ dependencies = [
 "checksum crossbeam-utils 0.2.2 (registry+https://github.com/rust-lang/crates.io-index)" = "2760899e32a1d58d5abb31129f8fae5de75220bc2176e77ff7c627ae45c918d9"
 "checksum crossbeam-utils 0.5.0 (registry+https://github.com/rust-lang/crates.io-index)" = "677d453a17e8bd2b913fa38e8b9cf04bcdbb5be790aa294f2389661d72036015"
 "checksum crossbeam-utils 0.6.5 (registry+https://github.com/rust-lang/crates.io-index)" = "f8306fcef4a7b563b76b7dd949ca48f52bc1141aa067d2ea09565f3e2652aa5c"
-"checksum cssparser 0.25.7 (registry+https://github.com/rust-lang/crates.io-index)" = "a921abc45ea75c2c817d951caeda31b94539d09a6b5e8d58a857b3b35c9c3894"
+"checksum cssparser 0.25.8 (registry+https://github.com/rust-lang/crates.io-index)" = "629648697bc0002c30e9e3775314e18d02935f43ecc8fa224140f40e8ffc7bb1"
 "checksum cssparser-macros 0.3.5 (registry+https://github.com/rust-lang/crates.io-index)" = "b16e382d9b983fdb9ac6a36b37fdeb84ce3ea81f749febfee3463cfa7f24275e"
 "checksum cstr 0.1.7 (registry+https://github.com/rust-lang/crates.io-index)" = "19f7a08ed4ecd7e077d4cee63937473e6f7cf57b702a9114ef41751b2cbc0f60"
 "checksum cstr-macros 0.1.5 (registry+https://github.com/rust-lang/crates.io-index)" = "0f12dd847ec773fc98d75edba5394cb87d0f35e7ee548a4c81849ca6374b3d48"
@@ -6085,7 +6086,7 @@ dependencies = [
 "checksum svg_fmt 0.4.0 (registry+https://github.com/rust-lang/crates.io-index)" = "c666f0fed8e1e20e057af770af9077d72f3d5a33157b8537c1475dd8ffd6d32b"
 "checksum sw-composite 0.5.3 (registry+https://github.com/rust-lang/crates.io-index)" = "a1638f200d9594cad22e9e58baf046382d8f5a38d40878db1705dcaeae239093"
 "checksum swapper 0.1.0 (registry+https://github.com/rust-lang/crates.io-index)" = "e454d048db5527d000bfddb77bd072bbf3a1e2ae785f16d9bd116e07c2ab45eb"
-"checksum syn 0.15.34 (registry+https://github.com/rust-lang/crates.io-index)" = "a1393e4a97a19c01e900df2aec855a29f71cf02c402e2f443b8d2747c25c5dbe"
+"checksum syn 0.15.39 (registry+https://github.com/rust-lang/crates.io-index)" = "b4d960b829a55e56db167e861ddb43602c003c7be0bee1d345021703fac2fb7c"
 "checksum synstructure 0.10.1 (registry+https://github.com/rust-lang/crates.io-index)" = "73687139bf99285483c96ac0add482c3776528beac1d97d444f6e91f203a2015"
 "checksum tempfile 3.0.8 (registry+https://github.com/rust-lang/crates.io-index)" = "7dc4738f2e68ed2855de5ac9cdbe05c9216773ecde4739b2f095002ab03a13ef"
 "checksum tendril 0.4.1 (registry+https://github.com/rust-lang/crates.io-index)" = "707feda9f2582d5d680d733e38755547a3e8fb471e7ba11452ecfd9ce93a5d3b"
diff --git a/components/background_hang_monitor/sampler_linux.rs b/components/background_hang_monitor/sampler_linux.rs
index 793783fc109..3b60203d208 100644
--- a/components/background_hang_monitor/sampler_linux.rs
+++ b/components/background_hang_monitor/sampler_linux.rs
@@ -64,15 +64,15 @@ struct PosixSemaphore {
 
 impl PosixSemaphore {
     pub fn new(value: u32) -> io::Result<Self> {
-        let mut sem: libc::sem_t = unsafe { mem::uninitialized() };
+        let mut sem = mem::MaybeUninit::uninit();
         let r = unsafe {
-            libc::sem_init(&mut sem, 0 /* not shared */, value)
+            libc::sem_init(sem.as_mut_ptr(), 0 /* not shared */, value)
         };
         if r == -1 {
             return Err(io::Error::last_os_error());
         }
         Ok(PosixSemaphore {
-            sem: UnsafeCell::new(sem),
+            sem: UnsafeCell::new(unsafe { sem.assume_init() }),
         })
     }
 
@@ -150,7 +150,7 @@ enum RegNum {
     Sp = UNW_REG_SP as isize,
 }
 
-fn get_register(cursor: &mut unw_cursor_t, num: RegNum) -> Result<u64, i32> {
+fn get_register(cursor: *mut unw_cursor_t, num: RegNum) -> Result<u64, i32> {
     unsafe {
         let mut val = 0;
         let ret = unw_get_reg(cursor, num as i32, &mut val);
@@ -162,7 +162,7 @@ fn get_register(cursor: &mut unw_cursor_t, num: RegNum) -> Result<u64, i32> {
     }
 }
 
-fn step(cursor: &mut unw_cursor_t) -> Result<bool, i32> {
+fn step(cursor: *mut unw_cursor_t) -> Result<bool, i32> {
     unsafe {
         // libunwind 1.1 seems to get confused and walks off the end of the stack. The last IP
         // it reports is 0, so we'll stop if we're there.
@@ -204,23 +204,23 @@ impl Sampler for LinuxSampler {
         }
 
         let context = unsafe { SHARED_STATE.context.load(Ordering::SeqCst) };
-        let mut cursor = unsafe { mem::uninitialized() };
-        let ret = unsafe { unw_init_local(&mut cursor, context) };
+        let mut cursor = mem::MaybeUninit::uninit();
+        let ret = unsafe { unw_init_local(cursor.as_mut_ptr(), context) };
         let result = if ret == UNW_ESUCCESS {
             let mut native_stack = NativeStack::new();
             loop {
-                let ip = match get_register(&mut cursor, RegNum::Ip) {
+                let ip = match get_register(cursor.as_mut_ptr(), RegNum::Ip) {
                     Ok(ip) => ip,
                     Err(_) => break,
                 };
-                let sp = match get_register(&mut cursor, RegNum::Sp) {
+                let sp = match get_register(cursor.as_mut_ptr(), RegNum::Sp) {
                     Ok(sp) => sp,
                     Err(_) => break,
                 };
                 if native_stack
                     .process_register(ip as *mut _, sp as *mut _)
                     .is_err() ||
-                    !step(&mut cursor).unwrap_or(false)
+                    !step(cursor.as_mut_ptr()).unwrap_or(false)
                 {
                     break;
                 }
diff --git a/components/script/dom/webglshader.rs b/components/script/dom/webglshader.rs
index bf63bdd3840..18ec81b1a98 100644
--- a/components/script/dom/webglshader.rs
+++ b/components/script/dom/webglshader.rs
@@ -21,7 +21,7 @@ use dom_struct::dom_struct;
 use mozangle::shaders::{BuiltInResources, Output, ShaderValidator};
 use std::cell::Cell;
 use std::os::raw::c_int;
-use std::sync::{Once, ONCE_INIT};
+use std::sync::Once;
 
 #[derive(Clone, Copy, Debug, JSTraceable, MallocSizeOf, PartialEq)]
 pub enum ShaderCompilationStatus {
@@ -42,7 +42,7 @@ pub struct WebGLShader {
     compilation_status: Cell<ShaderCompilationStatus>,
 }
 
-static GLSLANG_INITIALIZATION: Once = ONCE_INIT;
+static GLSLANG_INITIALIZATION: Once = Once::new();
 
 impl WebGLShader {
     fn new_inherited(context: &WebGLRenderingContext, id: WebGLShaderId, shader_type: u32) -> Self {
diff --git a/components/script/lib.rs b/components/script/lib.rs
index ef1c9f5a707..773c4eba812 100644
--- a/components/script/lib.rs
+++ b/components/script/lib.rs
@@ -106,14 +106,16 @@ use script_traits::SWManagerSenders;
 #[cfg(target_os = "linux")]
 #[allow(unsafe_code)]
 fn perform_platform_specific_initialization() {
-    use std::mem;
     // 4096 is default max on many linux systems
     const MAX_FILE_LIMIT: libc::rlim_t = 4096;
 
     // Bump up our number of file descriptors to save us from impending doom caused by an onslaught
     // of iframes.
     unsafe {
-        let mut rlim: libc::rlimit = mem::uninitialized();
+        let mut rlim = libc::rlimit {
+            rlim_cur: 0,
+            rlim_max: 0,
+        };
         match libc::getrlimit(libc::RLIMIT_NOFILE, &mut rlim) {
             0 => {
                 if rlim.rlim_cur >= MAX_FILE_LIMIT {