diff --git a/Cargo.lock b/Cargo.lock
index 6ebab21ef7b..e5b1799e879 100644
--- a/Cargo.lock
+++ b/Cargo.lock
@@ -182,19 +182,6 @@ dependencies = [
  "syntex_syntax 0.58.1 (registry+https://github.com/rust-lang/crates.io-index)",
 ]
 
-[[package]]
-name = "bit-set"
-version = "0.4.0"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-dependencies = [
- "bit-vec 0.4.3 (registry+https://github.com/rust-lang/crates.io-index)",
-]
-
-[[package]]
-name = "bit-vec"
-version = "0.4.3"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-
 [[package]]
 name = "bitflags"
 version = "0.5.0"
@@ -3600,11 +3587,10 @@ dependencies = [
 [[package]]
 name = "webrender"
 version = "0.50.0"
-source = "git+https://github.com/servo/webrender#7d9444a24fb98bcc41afdca2a5bf145d514500f1"
+source = "git+https://github.com/servo/webrender#aabd09368fbbbe7521874937a1b4d8bc628b9c40"
 dependencies = [
  "app_units 0.5.6 (registry+https://github.com/rust-lang/crates.io-index)",
  "bincode 0.8.0 (registry+https://github.com/rust-lang/crates.io-index)",
- "bit-set 0.4.0 (registry+https://github.com/rust-lang/crates.io-index)",
  "bitflags 0.9.1 (registry+https://github.com/rust-lang/crates.io-index)",
  "byteorder 1.0.0 (registry+https://github.com/rust-lang/crates.io-index)",
  "core-graphics 0.8.1 (registry+https://github.com/rust-lang/crates.io-index)",
@@ -3628,7 +3614,7 @@ dependencies = [
 [[package]]
 name = "webrender_api"
 version = "0.50.0"
-source = "git+https://github.com/servo/webrender#7d9444a24fb98bcc41afdca2a5bf145d514500f1"
+source = "git+https://github.com/servo/webrender#aabd09368fbbbe7521874937a1b4d8bc628b9c40"
 dependencies = [
  "app_units 0.5.6 (registry+https://github.com/rust-lang/crates.io-index)",
  "bincode 0.8.0 (registry+https://github.com/rust-lang/crates.io-index)",
@@ -3780,8 +3766,6 @@ dependencies = [
 "checksum binary-space-partition 0.1.2 (registry+https://github.com/rust-lang/crates.io-index)" = "88ceb0d16c4fd0e42876e298d7d3ce3780dd9ebdcbe4199816a32c77e08597ff"
 "checksum bincode 0.8.0 (registry+https://github.com/rust-lang/crates.io-index)" = "e103c8b299b28a9c6990458b7013dc4a8356a9b854c51b9883241f5866fac36e"
 "checksum bindgen 0.29.0 (registry+https://github.com/rust-lang/crates.io-index)" = "0c338079dafc81bef7d581f494b906603d12359c4306979eae6ca081925a4984"
-"checksum bit-set 0.4.0 (registry+https://github.com/rust-lang/crates.io-index)" = "d9bf6104718e80d7b26a68fdbacff3481cfc05df670821affc7e9cbc1884400c"
-"checksum bit-vec 0.4.3 (registry+https://github.com/rust-lang/crates.io-index)" = "5b97c2c8e8bbb4251754f559df8af22fb264853c7d009084a576cdf12565089d"
 "checksum bitflags 0.5.0 (registry+https://github.com/rust-lang/crates.io-index)" = "4f67931368edf3a9a51d29886d245f1c3db2f1ef0dcc9e35ff70341b78c10d23"
 "checksum bitflags 0.7.0 (registry+https://github.com/rust-lang/crates.io-index)" = "aad18937a628ec6abcd26d1489012cc0e18c21798210f491af69ded9b881106d"
 "checksum bitflags 0.8.2 (registry+https://github.com/rust-lang/crates.io-index)" = "1370e9fc2a6ae53aea8b7a5110edbd08836ed87c88736dfabccade1c2b44bff4"
diff --git a/components/layout/webrender_helpers.rs b/components/layout/webrender_helpers.rs
index 01ac993133c..55f13d38967 100644
--- a/components/layout/webrender_helpers.rs
+++ b/components/layout/webrender_helpers.rs
@@ -21,11 +21,13 @@ use webrender_api::{ExtendMode, LayoutTransform};
 
 fn prim_info(local_rect: Rect<Au>,
              local_clip: Option<webrender_api::LocalClip>) -> webrender_api::LayoutPrimitiveInfo {
-    webrender_api::LayoutPrimitiveInfo {
-        rect: local_rect.to_rectf(),
-        local_clip,
-        // TODO(gw): Make use of the WR backface visibility functionality.
-        is_backface_visible: true,
+    match local_clip {
+        Some(local_clip) => {
+            webrender_api::LayoutPrimitiveInfo::with_clip(local_rect.to_rectf(), local_clip)
+        }
+        None => {
+            webrender_api::LayoutPrimitiveInfo::new(local_rect.to_rectf())
+        }
     }
 }
 
diff --git a/tests/wpt/mozilla/meta/css/blur_a.html.ini b/tests/wpt/mozilla/meta/css/blur_a.html.ini
deleted file mode 100644
index ef40355e47a..00000000000
--- a/tests/wpt/mozilla/meta/css/blur_a.html.ini
+++ /dev/null
@@ -1,3 +0,0 @@
-[blur_a.html]
-  type: reftest
-  expected: FAIL