diff --git a/gfx/wr/webrender/src/prim_store/borders.rs b/gfx/wr/webrender/src/prim_store/borders.rs
index 4be7d72b46d4..183c7b9d907d 100644
--- a/gfx/wr/webrender/src/prim_store/borders.rs
+++ b/gfx/wr/webrender/src/prim_store/borders.rs
@@ -383,6 +383,6 @@ fn test_struct_sizes() {
     assert_eq!(mem::size_of::<NormalBorderTemplate>(), 216, "NormalBorderTemplate size changed");
     assert_eq!(mem::size_of::<NormalBorderKey>(), 104, "NormalBorderKey size changed");
     assert_eq!(mem::size_of::<ImageBorder>(), 84, "ImageBorder size changed");
-    assert_eq!(mem::size_of::<ImageBorderTemplate>(), 96, "ImageBorderTemplate size changed");
+    assert_eq!(mem::size_of::<ImageBorderTemplate>(), 104, "ImageBorderTemplate size changed");
     assert_eq!(mem::size_of::<ImageBorderKey>(), 104, "ImageBorderKey size changed");
 }
diff --git a/gfx/wr/webrender/src/prim_store/gradient/mod.rs b/gfx/wr/webrender/src/prim_store/gradient/mod.rs
index 3fea0bb543fc..be501bfd4721 100644
--- a/gfx/wr/webrender/src/prim_store/gradient/mod.rs
+++ b/gfx/wr/webrender/src/prim_store/gradient/mod.rs
@@ -375,14 +375,14 @@ fn test_struct_sizes() {
     // (b) You made a structure larger. This is not necessarily a problem, but should only
     //     be done with care, and after checking if talos performance regresses badly.
     assert_eq!(mem::size_of::<LinearGradient>(), 72, "LinearGradient size changed");
-    assert_eq!(mem::size_of::<LinearGradientTemplate>(), 144, "LinearGradientTemplate size changed");
+    assert_eq!(mem::size_of::<LinearGradientTemplate>(), 152, "LinearGradientTemplate size changed");
     assert_eq!(mem::size_of::<LinearGradientKey>(), 88, "LinearGradientKey size changed");
 
     assert_eq!(mem::size_of::<RadialGradient>(), 72, "RadialGradient size changed");
-    assert_eq!(mem::size_of::<RadialGradientTemplate>(), 144, "RadialGradientTemplate size changed");
+    assert_eq!(mem::size_of::<RadialGradientTemplate>(), 152, "RadialGradientTemplate size changed");
     assert_eq!(mem::size_of::<RadialGradientKey>(), 96, "RadialGradientKey size changed");
 
     assert_eq!(mem::size_of::<ConicGradient>(), 72, "ConicGradient size changed");
-    assert_eq!(mem::size_of::<ConicGradientTemplate>(), 144, "ConicGradientTemplate size changed");
+    assert_eq!(mem::size_of::<ConicGradientTemplate>(), 152, "ConicGradientTemplate size changed");
     assert_eq!(mem::size_of::<ConicGradientKey>(), 96, "ConicGradientKey size changed");
 }
diff --git a/gfx/wr/webrender/src/prim_store/image.rs b/gfx/wr/webrender/src/prim_store/image.rs
index 3e4ed4a896fc..451e01236b71 100644
--- a/gfx/wr/webrender/src/prim_store/image.rs
+++ b/gfx/wr/webrender/src/prim_store/image.rs
@@ -676,6 +676,6 @@ fn test_struct_sizes() {
     assert_eq!(mem::size_of::<ImageTemplate>(), 72, "ImageTemplate size changed");
     assert_eq!(mem::size_of::<ImageKey>(), 52, "ImageKey size changed");
     assert_eq!(mem::size_of::<YuvImage>(), 32, "YuvImage size changed");
-    assert_eq!(mem::size_of::<YuvImageTemplate>(), 72, "YuvImageTemplate size changed");
+    assert_eq!(mem::size_of::<YuvImageTemplate>(), 84, "YuvImageTemplate size changed");
     assert_eq!(mem::size_of::<YuvImageKey>(), 52, "YuvImageKey size changed");
 }
diff --git a/gfx/wr/webrender/src/render_task_graph.rs b/gfx/wr/webrender/src/render_task_graph.rs
index aa089a15d3a3..c76c925a4072 100644
--- a/gfx/wr/webrender/src/render_task_graph.rs
+++ b/gfx/wr/webrender/src/render_task_graph.rs
@@ -51,7 +51,7 @@ impl<'l> RenderTaskAllocation<'l> {
     #[inline(always)]
     pub fn init(self, value: RenderTask) -> RenderTaskId {
         RenderTaskId {
-            index: self.alloc.init(value) as u16,
+            index: self.alloc.init(value) as u32,
         }
     }
 }
@@ -61,12 +61,12 @@ impl<'l> RenderTaskAllocation<'l> {
 #[cfg_attr(feature = "capture", derive(Serialize))]
 #[cfg_attr(feature = "replay", derive(Deserialize))]
 pub struct RenderTaskId {
-    pub index: u16,
+    pub index: u32,
 }
 
 impl RenderTaskId {
     pub const INVALID: RenderTaskId = RenderTaskId {
-        index: u16::MAX,
+        index: u32::MAX,
     };
 }
 
@@ -264,7 +264,7 @@ impl RenderTaskGraphBuilder {
     pub fn add(&mut self) -> RenderTaskAllocation {
         // Assume every task is a root to start with
         self.roots.insert(
-            RenderTaskId { index: self.tasks.len() as u16 }
+            RenderTaskId { index: self.tasks.len() as u32 }
         );
 
         RenderTaskAllocation {
@@ -385,7 +385,7 @@ impl RenderTaskGraphBuilder {
         // Determine which pass each task can be freed on, which depends on which is
         // the last task that has this as an input.
         for i in 0 .. graph.tasks.len() {
-            let task_id = RenderTaskId { index: i as u16 };
+            let task_id = RenderTaskId { index: i as u32 };
             assign_free_pass(
                 task_id,
                 &mut self.child_task_buffer,
@@ -405,7 +405,7 @@ impl RenderTaskGraphBuilder {
         // Assign tasks to each pass based on their `render_on` attribute
         for (index, task) in graph.tasks.iter().enumerate() {
             if task.kind.is_a_rendering_operation() {
-                let id = RenderTaskId { index: index as u16 };
+                let id = RenderTaskId { index: index as u32 };
                 graph.passes[task.render_on.0].task_ids.push(id);
             }
         }