Make OffscreenCanvas animation in sync with its placeholder canvas's parent frame rate

third_party/WebKit/public/platform/modules/offscreencanvas/offscreen_canvas_surface.mojom

 // Copyright 2016 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 module blink.mojom;
 
 import "cc/ipc/compositor_frame.mojom";
 import "cc/ipc/frame_sink_id.mojom";
 import "cc/ipc/mojo_compositor_frame_sink.mojom";
 import "cc/ipc/surface_id.mojom";
 import "cc/ipc/surface_info.mojom";
 import "cc/ipc/surface_sequence.mojom";
 
 interface OffscreenCanvasSurface {
   Require(cc.mojom.SurfaceId surface_id, cc.mojom.SurfaceSequence sequence);
   Satisfy(cc.mojom.SurfaceSequence sequence);
 };
 
 interface OffscreenCanvasSurfaceClient {
   // TODO(fsamuel, xlai): Replace this with DisplayCompositorClient
   OnSurfaceCreated(cc.mojom.SurfaceInfo surface_info);
 };
 
 interface OffscreenCanvasSurfaceFactory {
-  CreateOffscreenCanvasSurface(cc.mojom.FrameSinkId frame_sink_id,
+  CreateOffscreenCanvasSurface(cc.mojom.FrameSinkId parent_frame_sink_id,
+                               cc.mojom.FrameSinkId frame_sink_id,
                                OffscreenCanvasSurfaceClient client,
                                OffscreenCanvasSurface& service);
 };
 
 interface OffscreenCanvasCompositorFrameSinkProvider {
   // TODO(fsamuel, xlai): Replace this with DisplayCompositor
   CreateCompositorFrameSink(cc.mojom.FrameSinkId frame_sink_id,
                             cc.mojom.MojoCompositorFrameSinkClient client,
                             cc.mojom.MojoCompositorFrameSink& sink);
 };