--- a/gfx/webrender_bindings/webrender_ffi_generated.h
+++ b/gfx/webrender_bindings/webrender_ffi_generated.h
@@ -36,16 +36,23 @@ enum class BorderStyle : uint32_t {
 
 enum class BoxShadowClipMode : uint32_t {
   Outset = 0,
   Inset = 1,
 
   Sentinel /* this must be last for serialization purposes. */
 };
 
+enum class ClipMode {
+  Clip = 0,
+  ClipOut = 1,
+
+  Sentinel /* this must be last for serialization purposes. */
+};
+
 enum class ExtendMode : uint32_t {
   Clamp = 0,
   Repeat = 1,
 
   Sentinel /* this must be last for serialization purposes. */
 };
 
 enum class ExternalImageType : uint32_t {
@@ -445,20 +452,24 @@ struct BorderRadius {
   }
 };
 
 struct ComplexClipRegion {
   // The boundaries of the rectangle.
   LayoutRect rect;
   // Border radii of this rectangle.
   BorderRadius radii;
+  // Whether we are clipping inside or outside
+  // the region.
+  ClipMode mode;
 
   bool operator==(const ComplexClipRegion& aOther) const {
     return rect == aOther.rect &&
-           radii == aOther.radii;
+           radii == aOther.radii &&
+           mode == aOther.mode;
   }
 };
 
 struct ImageKey {
   IdNamespace mNamespace;
   uint32_t mHandle;
 
   bool operator==(const ImageKey& aOther) const {

--- a/toolkit/library/gtest/rust/Cargo.lock
+++ b/toolkit/library/gtest/rust/Cargo.lock
@@ -1542,17 +1542,17 @@ source = "registry+https://github.com/ru
 dependencies = [
  "kernel32-sys 0.2.2 (registry+https://github.com/rust-lang/crates.io-index)",
  "same-file 0.1.3 (registry+https://github.com/rust-lang/crates.io-index)",
  "winapi 0.2.8 (registry+https://github.com/rust-lang/crates.io-index)",
 ]
 
 [[package]]
 name = "webrender"
-version = "0.52.1"
+version = "0.53.0"
 dependencies = [
  "app_units 0.5.6 (registry+https://github.com/rust-lang/crates.io-index)",
  "bincode 0.9.1 (registry+https://github.com/rust-lang/crates.io-index)",
  "bitflags 1.0.0 (registry+https://github.com/rust-lang/crates.io-index)",
  "byteorder 1.0.0 (registry+https://github.com/rust-lang/crates.io-index)",
  "core-foundation 0.4.4 (registry+https://github.com/rust-lang/crates.io-index)",
  "core-graphics 0.9.1 (registry+https://github.com/rust-lang/crates.io-index)",
  "core-text 7.0.0 (registry+https://github.com/rust-lang/crates.io-index)",
@@ -1564,48 +1564,47 @@ dependencies = [
  "gleam 0.4.8 (registry+https://github.com/rust-lang/crates.io-index)",
  "lazy_static 0.2.8 (registry+https://github.com/rust-lang/crates.io-index)",
  "log 0.3.8 (registry+https://github.com/rust-lang/crates.io-index)",
  "num-traits 0.1.39 (registry+https://github.com/rust-lang/crates.io-index)",
  "plane-split 0.6.0 (registry+https://github.com/rust-lang/crates.io-index)",
  "rayon 0.8.2 (registry+https://github.com/rust-lang/crates.io-index)",
  "thread_profiler 0.1.1 (registry+https://github.com/rust-lang/crates.io-index)",
  "time 0.1.36 (registry+https://github.com/rust-lang/crates.io-index)",
- "webrender_api 0.52.1",
+ "webrender_api 0.53.0",
 ]
 
 [[package]]
 name = "webrender_api"
-version = "0.52.1"
+version = "0.53.0"
 dependencies = [
  "app_units 0.5.6 (registry+https://github.com/rust-lang/crates.io-index)",
  "bincode 0.9.1 (registry+https://github.com/rust-lang/crates.io-index)",
  "bitflags 1.0.0 (registry+https://github.com/rust-lang/crates.io-index)",
  "byteorder 1.0.0 (registry+https://github.com/rust-lang/crates.io-index)",
  "core-foundation 0.4.4 (registry+https://github.com/rust-lang/crates.io-index)",
  "core-graphics 0.9.1 (registry+https://github.com/rust-lang/crates.io-index)",
  "dwrote 0.4.0 (registry+https://github.com/rust-lang/crates.io-index)",
  "euclid 0.15.2 (registry+https://github.com/rust-lang/crates.io-index)",
- "heapsize 0.4.0 (registry+https://github.com/rust-lang/crates.io-index)",
  "serde 1.0.8 (registry+https://github.com/rust-lang/crates.io-index)",
  "time 0.1.36 (registry+https://github.com/rust-lang/crates.io-index)",
 ]
 
 [[package]]
 name = "webrender_bindings"
 version = "0.1.0"
 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)",
  "euclid 0.15.2 (registry+https://github.com/rust-lang/crates.io-index)",
  "gleam 0.4.8 (registry+https://github.com/rust-lang/crates.io-index)",
  "rayon 0.8.2 (registry+https://github.com/rust-lang/crates.io-index)",
  "thread_profiler 0.1.1 (registry+https://github.com/rust-lang/crates.io-index)",
- "webrender 0.52.1",
- "webrender_api 0.52.1",
+ "webrender 0.53.0",
+ "webrender_api 0.53.0",
 ]
 
 [[package]]
 name = "winapi"
 version = "0.2.8"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 
 [[package]]

--- a/toolkit/library/rust/Cargo.lock
+++ b/toolkit/library/rust/Cargo.lock
@@ -1554,17 +1554,17 @@ source = "registry+https://github.com/ru
 dependencies = [
  "kernel32-sys 0.2.2 (registry+https://github.com/rust-lang/crates.io-index)",
  "same-file 0.1.3 (registry+https://github.com/rust-lang/crates.io-index)",
  "winapi 0.2.8 (registry+https://github.com/rust-lang/crates.io-index)",
 ]
 
 [[package]]
 name = "webrender"
-version = "0.52.1"
+version = "0.53.0"
 dependencies = [
  "app_units 0.5.6 (registry+https://github.com/rust-lang/crates.io-index)",
  "bincode 0.9.1 (registry+https://github.com/rust-lang/crates.io-index)",
  "bitflags 1.0.0 (registry+https://github.com/rust-lang/crates.io-index)",
  "byteorder 1.0.0 (registry+https://github.com/rust-lang/crates.io-index)",
  "core-foundation 0.4.4 (registry+https://github.com/rust-lang/crates.io-index)",
  "core-graphics 0.9.1 (registry+https://github.com/rust-lang/crates.io-index)",
  "core-text 7.0.0 (registry+https://github.com/rust-lang/crates.io-index)",
@@ -1576,48 +1576,47 @@ dependencies = [
  "gleam 0.4.8 (registry+https://github.com/rust-lang/crates.io-index)",
  "lazy_static 0.2.8 (registry+https://github.com/rust-lang/crates.io-index)",
  "log 0.3.8 (registry+https://github.com/rust-lang/crates.io-index)",
  "num-traits 0.1.39 (registry+https://github.com/rust-lang/crates.io-index)",
  "plane-split 0.6.0 (registry+https://github.com/rust-lang/crates.io-index)",
  "rayon 0.8.2 (registry+https://github.com/rust-lang/crates.io-index)",
  "thread_profiler 0.1.1 (registry+https://github.com/rust-lang/crates.io-index)",
  "time 0.1.36 (registry+https://github.com/rust-lang/crates.io-index)",
- "webrender_api 0.52.1",
+ "webrender_api 0.53.0",
 ]
 
 [[package]]
 name = "webrender_api"
-version = "0.52.1"
+version = "0.53.0"
 dependencies = [
  "app_units 0.5.6 (registry+https://github.com/rust-lang/crates.io-index)",
  "bincode 0.9.1 (registry+https://github.com/rust-lang/crates.io-index)",
  "bitflags 1.0.0 (registry+https://github.com/rust-lang/crates.io-index)",
  "byteorder 1.0.0 (registry+https://github.com/rust-lang/crates.io-index)",
  "core-foundation 0.4.4 (registry+https://github.com/rust-lang/crates.io-index)",
  "core-graphics 0.9.1 (registry+https://github.com/rust-lang/crates.io-index)",
  "dwrote 0.4.0 (registry+https://github.com/rust-lang/crates.io-index)",
  "euclid 0.15.2 (registry+https://github.com/rust-lang/crates.io-index)",
- "heapsize 0.4.0 (registry+https://github.com/rust-lang/crates.io-index)",
  "serde 1.0.8 (registry+https://github.com/rust-lang/crates.io-index)",
  "time 0.1.36 (registry+https://github.com/rust-lang/crates.io-index)",
 ]
 
 [[package]]
 name = "webrender_bindings"
 version = "0.1.0"
 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)",
  "euclid 0.15.2 (registry+https://github.com/rust-lang/crates.io-index)",
  "gleam 0.4.8 (registry+https://github.com/rust-lang/crates.io-index)",
  "rayon 0.8.2 (registry+https://github.com/rust-lang/crates.io-index)",
  "thread_profiler 0.1.1 (registry+https://github.com/rust-lang/crates.io-index)",
- "webrender 0.52.1",
- "webrender_api 0.52.1",
+ "webrender 0.53.0",
+ "webrender_api 0.53.0",
 ]
 
 [[package]]
 name = "winapi"
 version = "0.2.8"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 
 [[package]]