Pass Surface ID namespace to renderer compositors.

content/browser/renderer_host/render_widget_host_view_mac.mm

 // Copyright (c) 2012 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.
 
 #include "content/browser/renderer_host/render_widget_host_view_mac.h"
 
 #import <objc/runtime.h>
 #include <OpenGL/gl.h>
 #include <QuartzCore/QuartzCore.h>
 
@@ skipping 1545 matching lines @@
 void RenderWidgetHostViewMac::WheelEventAck(
     const blink::WebMouseWheelEvent& event,
     InputEventAckState ack_result) {
   bool consumed = ack_result == INPUT_EVENT_ACK_STATE_CONSUMED;
   // Only record a wheel event as unhandled if JavaScript handlers got a chance
   // to see it (no-op wheel events are ignored by the event dispatcher)
   if (event.deltaX || event.deltaY)
     [cocoa_view_ processedWheelEvent:event consumed:consumed];
 }
 
+uint32_t RenderWidgetHostViewMac::GetSurfaceIdNamespace() {
+  if (delegated_frame_host_)

[dcheng, 2015/05/14 14:53:38]

Can we add a comment that explains why this can happen on Mac but not Aura?

+    return delegated_frame_host_->GetSurfaceIdNamespace();
+
+  return 0;
+}
+
 bool RenderWidgetHostViewMac::Send(IPC::Message* message) {
   if (render_widget_host_)
     return render_widget_host_->Send(message);
   delete message;
   return false;
 }
 
 void RenderWidgetHostViewMac::ShutdownHost() {
   weak_factory_.InvalidateWeakPtrs();
   render_widget_host_->Shutdown();
@@ skipping 1914 matching lines @@
 
 // "-webkit-app-region: drag | no-drag" is implemented on Mac by excluding
 // regions that are not draggable. (See ControlRegionView in
 // native_app_window_cocoa.mm). This requires the render host view to be
 // draggable by default.
 - (BOOL)mouseDownCanMoveWindow {
   return YES;
 }
 
 @end