diff --git a/Cargo.lock b/Cargo.lock
index b1af7250f6d..b0091bc7fc2 100644
--- a/Cargo.lock
+++ b/Cargo.lock
@@ -3160,7 +3160,7 @@ dependencies = [
 [[package]]
 name = "webrender"
 version = "0.21.0"
-source = "git+https://github.com/servo/webrender#9565e58d2636108415009ba76690a5dff9019c52"
+source = "git+https://github.com/servo/webrender#040805f31650527311c0a0d58ccf9620b0f3eca9"
 dependencies = [
  "app_units 0.4.0 (registry+https://github.com/rust-lang/crates.io-index)",
  "bincode 1.0.0-alpha2 (registry+https://github.com/rust-lang/crates.io-index)",
@@ -3188,7 +3188,7 @@ dependencies = [
 [[package]]
 name = "webrender_traits"
 version = "0.22.0"
-source = "git+https://github.com/servo/webrender#9565e58d2636108415009ba76690a5dff9019c52"
+source = "git+https://github.com/servo/webrender#040805f31650527311c0a0d58ccf9620b0f3eca9"
 dependencies = [
  "app_units 0.4.0 (registry+https://github.com/rust-lang/crates.io-index)",
  "byteorder 1.0.0 (registry+https://github.com/rust-lang/crates.io-index)",
diff --git a/tests/wpt/metadata-css/compositing-1_dev/html/mix-blend-mode-blended-element-interposed.htm.ini b/tests/wpt/metadata-css/compositing-1_dev/html/mix-blend-mode-blended-element-interposed.htm.ini
deleted file mode 100644
index 3d003b5735e..00000000000
--- a/tests/wpt/metadata-css/compositing-1_dev/html/mix-blend-mode-blended-element-interposed.htm.ini
+++ /dev/null
@@ -1,4 +0,0 @@
-[mix-blend-mode-blended-element-interposed.htm]
-  type: reftest
-  expected:
-    if os == "linux": FAIL
diff --git a/tests/wpt/metadata-css/compositing-1_dev/html/mix-blend-mode-blended-element-overflow-hidden-and-border-radius.htm.ini b/tests/wpt/metadata-css/compositing-1_dev/html/mix-blend-mode-blended-element-overflow-hidden-and-border-radius.htm.ini
index 0c1ff8c8424..19049dffb5c 100644
--- a/tests/wpt/metadata-css/compositing-1_dev/html/mix-blend-mode-blended-element-overflow-hidden-and-border-radius.htm.ini
+++ b/tests/wpt/metadata-css/compositing-1_dev/html/mix-blend-mode-blended-element-overflow-hidden-and-border-radius.htm.ini
@@ -1,4 +1,3 @@
 [mix-blend-mode-blended-element-overflow-hidden-and-border-radius.htm]
   type: reftest
-  expected:
-    if os == "linux": FAIL
+  expected: FAIL
diff --git a/tests/wpt/metadata-css/compositing-1_dev/html/mix-blend-mode-blended-element-overflow-scroll.htm.ini b/tests/wpt/metadata-css/compositing-1_dev/html/mix-blend-mode-blended-element-overflow-scroll.htm.ini
deleted file mode 100644
index c2917db7804..00000000000
--- a/tests/wpt/metadata-css/compositing-1_dev/html/mix-blend-mode-blended-element-overflow-scroll.htm.ini
+++ /dev/null
@@ -1,5 +0,0 @@
-[mix-blend-mode-blended-element-overflow-scroll.htm]
-  type: reftest
-  expected:
-    if os == "linux": FAIL
-
diff --git a/tests/wpt/metadata-css/compositing-1_dev/html/mix-blend-mode-blended-element-with-transparent-pixels.htm.ini b/tests/wpt/metadata-css/compositing-1_dev/html/mix-blend-mode-blended-element-with-transparent-pixels.htm.ini
deleted file mode 100644
index c9393220e8e..00000000000
--- a/tests/wpt/metadata-css/compositing-1_dev/html/mix-blend-mode-blended-element-with-transparent-pixels.htm.ini
+++ /dev/null
@@ -1,3 +0,0 @@
-[mix-blend-mode-blended-element-with-transparent-pixels.htm]
-  type: reftest
-  expected: FAIL
diff --git a/tests/wpt/metadata-css/compositing-1_dev/html/mix-blend-mode-blending-with-sibling.htm.ini b/tests/wpt/metadata-css/compositing-1_dev/html/mix-blend-mode-blending-with-sibling.htm.ini
deleted file mode 100644
index 4e85de2d02a..00000000000
--- a/tests/wpt/metadata-css/compositing-1_dev/html/mix-blend-mode-blending-with-sibling.htm.ini
+++ /dev/null
@@ -1,4 +0,0 @@
-[mix-blend-mode-blending-with-sibling.htm]
-  type: reftest
-  expected:
-    if os == "linux": FAIL
diff --git a/tests/wpt/metadata-css/compositing-1_dev/html/mix-blend-mode-canvas-parent.htm.ini b/tests/wpt/metadata-css/compositing-1_dev/html/mix-blend-mode-canvas-parent.htm.ini
deleted file mode 100644
index f62c9362dc8..00000000000
--- a/tests/wpt/metadata-css/compositing-1_dev/html/mix-blend-mode-canvas-parent.htm.ini
+++ /dev/null
@@ -1,4 +0,0 @@
-[mix-blend-mode-canvas-parent.htm]
-  type: reftest
-  expected:
-    if os == "linux": FAIL
diff --git a/tests/wpt/metadata-css/compositing-1_dev/html/mix-blend-mode-canvas-sibling.htm.ini b/tests/wpt/metadata-css/compositing-1_dev/html/mix-blend-mode-canvas-sibling.htm.ini
deleted file mode 100644
index bdcfe8de66d..00000000000
--- a/tests/wpt/metadata-css/compositing-1_dev/html/mix-blend-mode-canvas-sibling.htm.ini
+++ /dev/null
@@ -1,4 +0,0 @@
-[mix-blend-mode-canvas-sibling.htm]
-  type: reftest
-  expected:
-    if os == "linux": FAIL
diff --git a/tests/wpt/metadata-css/compositing-1_dev/html/mix-blend-mode-iframe-parent.htm.ini b/tests/wpt/metadata-css/compositing-1_dev/html/mix-blend-mode-iframe-parent.htm.ini
deleted file mode 100644
index 40feb105201..00000000000
--- a/tests/wpt/metadata-css/compositing-1_dev/html/mix-blend-mode-iframe-parent.htm.ini
+++ /dev/null
@@ -1,5 +0,0 @@
-[mix-blend-mode-iframe-parent.htm]
-  type: reftest
-  expected:
-    if os == "linux": FAIL
-
diff --git a/tests/wpt/metadata-css/compositing-1_dev/html/mix-blend-mode-iframe-sibling.htm.ini b/tests/wpt/metadata-css/compositing-1_dev/html/mix-blend-mode-iframe-sibling.htm.ini
deleted file mode 100644
index 2b2cdb197e9..00000000000
--- a/tests/wpt/metadata-css/compositing-1_dev/html/mix-blend-mode-iframe-sibling.htm.ini
+++ /dev/null
@@ -1,5 +0,0 @@
-[mix-blend-mode-iframe-sibling.htm]
-  type: reftest
-  expected:
-    if os == "linux": FAIL
-
diff --git a/tests/wpt/metadata-css/compositing-1_dev/html/mix-blend-mode-intermediate-element-overflow-hidden-and-border-radius.htm.ini b/tests/wpt/metadata-css/compositing-1_dev/html/mix-blend-mode-intermediate-element-overflow-hidden-and-border-radius.htm.ini
deleted file mode 100644
index b5188507ca0..00000000000
--- a/tests/wpt/metadata-css/compositing-1_dev/html/mix-blend-mode-intermediate-element-overflow-hidden-and-border-radius.htm.ini
+++ /dev/null
@@ -1,4 +0,0 @@
-[mix-blend-mode-intermediate-element-overflow-hidden-and-border-radius.htm]
-  type: reftest
-  expected:
-    if os == "linux": FAIL
diff --git a/tests/wpt/metadata-css/compositing-1_dev/html/mix-blend-mode-mask.htm.ini b/tests/wpt/metadata-css/compositing-1_dev/html/mix-blend-mode-mask.htm.ini
deleted file mode 100644
index 65fcc7b2acd..00000000000
--- a/tests/wpt/metadata-css/compositing-1_dev/html/mix-blend-mode-mask.htm.ini
+++ /dev/null
@@ -1,4 +0,0 @@
-[mix-blend-mode-mask.htm]
-  type: reftest
-  expected:
-    if os == "linux": FAIL
diff --git a/tests/wpt/metadata-css/compositing-1_dev/html/mix-blend-mode-overflowing-child-of-blended-element.htm.ini b/tests/wpt/metadata-css/compositing-1_dev/html/mix-blend-mode-overflowing-child-of-blended-element.htm.ini
deleted file mode 100644
index 6a32d5e9df9..00000000000
--- a/tests/wpt/metadata-css/compositing-1_dev/html/mix-blend-mode-overflowing-child-of-blended-element.htm.ini
+++ /dev/null
@@ -1,3 +0,0 @@
-[mix-blend-mode-overflowing-child-of-blended-element.htm]
-  type: reftest
-  expected: FAIL
diff --git a/tests/wpt/metadata-css/compositing-1_dev/html/mix-blend-mode-overflowing-child.htm.ini b/tests/wpt/metadata-css/compositing-1_dev/html/mix-blend-mode-overflowing-child.htm.ini
deleted file mode 100644
index 4a3260f5cd4..00000000000
--- a/tests/wpt/metadata-css/compositing-1_dev/html/mix-blend-mode-overflowing-child.htm.ini
+++ /dev/null
@@ -1,3 +0,0 @@
-[mix-blend-mode-overflowing-child.htm]
-  type: reftest
-  expected: FAIL
diff --git a/tests/wpt/metadata-css/compositing-1_dev/html/mix-blend-mode-paragraph.htm.ini b/tests/wpt/metadata-css/compositing-1_dev/html/mix-blend-mode-paragraph.htm.ini
deleted file mode 100644
index e352d6dd0e1..00000000000
--- a/tests/wpt/metadata-css/compositing-1_dev/html/mix-blend-mode-paragraph.htm.ini
+++ /dev/null
@@ -1,3 +0,0 @@
-[mix-blend-mode-paragraph.htm]
-  type: reftest
-  expected: FAIL
diff --git a/tests/wpt/metadata-css/compositing-1_dev/html/mix-blend-mode-parent-element-overflow-scroll.htm.ini b/tests/wpt/metadata-css/compositing-1_dev/html/mix-blend-mode-parent-element-overflow-scroll.htm.ini
index 57d07e5fa46..978aa0d6dea 100644
--- a/tests/wpt/metadata-css/compositing-1_dev/html/mix-blend-mode-parent-element-overflow-scroll.htm.ini
+++ b/tests/wpt/metadata-css/compositing-1_dev/html/mix-blend-mode-parent-element-overflow-scroll.htm.ini
@@ -1,4 +1,3 @@
 [mix-blend-mode-parent-element-overflow-scroll.htm]
   type: reftest
-  expected:
-    if os == "linux": FAIL
+  expected: FAIL
diff --git a/tests/wpt/metadata-css/compositing-1_dev/html/mix-blend-mode-parent-with-3D-transform.htm.ini b/tests/wpt/metadata-css/compositing-1_dev/html/mix-blend-mode-parent-with-3D-transform.htm.ini
index 1d74c3281f7..ad8f727beaf 100644
--- a/tests/wpt/metadata-css/compositing-1_dev/html/mix-blend-mode-parent-with-3D-transform.htm.ini
+++ b/tests/wpt/metadata-css/compositing-1_dev/html/mix-blend-mode-parent-with-3D-transform.htm.ini
@@ -1,3 +1,4 @@
 [mix-blend-mode-parent-with-3D-transform.htm]
   type: reftest
-  expected: FAIL
+  expected:
+    if os == "mac": FAIL
diff --git a/tests/wpt/metadata-css/compositing-1_dev/html/mix-blend-mode-parent-with-text.htm.ini b/tests/wpt/metadata-css/compositing-1_dev/html/mix-blend-mode-parent-with-text.htm.ini
deleted file mode 100644
index b2721b213c9..00000000000
--- a/tests/wpt/metadata-css/compositing-1_dev/html/mix-blend-mode-parent-with-text.htm.ini
+++ /dev/null
@@ -1,3 +0,0 @@
-[mix-blend-mode-parent-with-text.htm]
-  type: reftest
-  expected: FAIL
diff --git a/tests/wpt/metadata-css/compositing-1_dev/html/mix-blend-mode-script.htm.ini b/tests/wpt/metadata-css/compositing-1_dev/html/mix-blend-mode-script.htm.ini
deleted file mode 100644
index ea00a28f767..00000000000
--- a/tests/wpt/metadata-css/compositing-1_dev/html/mix-blend-mode-script.htm.ini
+++ /dev/null
@@ -1,4 +0,0 @@
-[mix-blend-mode-script.htm]
-  type: reftest
-  expected:
-    if os == "linux": FAIL
diff --git a/tests/wpt/metadata-css/compositing-1_dev/html/mix-blend-mode-sibling-with-3D-transform.htm.ini b/tests/wpt/metadata-css/compositing-1_dev/html/mix-blend-mode-sibling-with-3D-transform.htm.ini
deleted file mode 100644
index 4609d9e42a9..00000000000
--- a/tests/wpt/metadata-css/compositing-1_dev/html/mix-blend-mode-sibling-with-3D-transform.htm.ini
+++ /dev/null
@@ -1,3 +0,0 @@
-[mix-blend-mode-sibling-with-3D-transform.htm]
-  type: reftest
-  expected: FAIL
diff --git a/tests/wpt/metadata-css/compositing-1_dev/html/mix-blend-mode-simple.htm.ini b/tests/wpt/metadata-css/compositing-1_dev/html/mix-blend-mode-simple.htm.ini
deleted file mode 100644
index 686841df84f..00000000000
--- a/tests/wpt/metadata-css/compositing-1_dev/html/mix-blend-mode-simple.htm.ini
+++ /dev/null
@@ -1,4 +0,0 @@
-[mix-blend-mode-simple.htm]
-  type: reftest
-  expected:
-    if os == "linux": FAIL
diff --git a/tests/wpt/metadata-css/compositing-1_dev/html/mix-blend-mode-transition.htm.ini b/tests/wpt/metadata-css/compositing-1_dev/html/mix-blend-mode-transition.htm.ini
deleted file mode 100644
index 67383d2ec67..00000000000
--- a/tests/wpt/metadata-css/compositing-1_dev/html/mix-blend-mode-transition.htm.ini
+++ /dev/null
@@ -1,4 +0,0 @@
-[mix-blend-mode-transition.htm]
-  type: reftest
-  expected:
-    if os == "linux": FAIL