Send FrameSwapMessageQueue's messages with a separate IPC

cc/ipc/compositor_frame_metadata_struct_traits.h

Index: cc/ipc/compositor_frame_metadata_struct_traits.h
diff --git a/cc/ipc/compositor_frame_metadata_struct_traits.h b/cc/ipc/compositor_frame_metadata_struct_traits.h
index 29c3ca4079393644822c2ce73ec923607144b140..46bb130d42b799e7350f17787c714980d6e9cb36 100644
--- a/cc/ipc/compositor_frame_metadata_struct_traits.h
+++ b/cc/ipc/compositor_frame_metadata_struct_traits.h
@@ -121,6 +121,10 @@ struct StructTraits<cc::mojom::CompositorFrameMetadataDataView,
     return metadata.begin_frame_ack;
   }
 
+  static uint32_t frame_token(const cc::CompositorFrameMetadata& metadata) {
+    return metadata.frame_token;
+  }
+
   static bool Read(cc::mojom::CompositorFrameMetadataDataView data,
                    cc::CompositorFrameMetadata* out);
 };