Implement RenderPass StructTraits

cc/ipc/traits_test_service.mojom

Index: cc/ipc/traits_test_service.mojom
diff --git a/cc/ipc/traits_test_service.mojom b/cc/ipc/traits_test_service.mojom
index 3005db3811f3ce737f64aec064a03c505457812b..7c5b45641f4b56099985e4f24e038cc0a05b498e 100644
--- a/cc/ipc/traits_test_service.mojom
+++ b/cc/ipc/traits_test_service.mojom
@@ -9,6 +9,7 @@ import "cc/ipc/compositor_frame_metadata.mojom";
 import "cc/ipc/filter_operation.mojom";
 import "cc/ipc/filter_operations.mojom";
 import "cc/ipc/quads.mojom";
+import "cc/ipc/render_pass.mojom";
 import "cc/ipc/render_pass_id.mojom";
 import "cc/ipc/returned_resource.mojom";
 import "cc/ipc/selection.mojom";
@@ -37,6 +38,9 @@ interface TraitsTestService {
   EchoQuadList(QuadList q) => (QuadList pass);
 
   [Sync]
+  EchoRenderPass(RenderPass r) => (RenderPass pass);
+
+  [Sync]
   EchoRenderPassId(RenderPassId r) => (RenderPassId pass);
 
   [Sync]