Add IPC allowing GPU process to tell browser process to temporarily drop a front buffer.

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"
 
 #include <QuartzCore/QuartzCore.h>
 
 #include "base/bind.h"
 #include "base/debug/trace_event.h"
@@ skipping 915 matching lines @@
     if (plugin_container_manager_.SurfaceShouldBeVisible(params.window))
       [view setHidden:NO];
     [view drawView];
   }
 
   if (params.route_id != 0) {
     RenderWidgetHost::AcknowledgePostSubBuffer(params.route_id, gpu_host_id);
   }
 }
 
+void RenderWidgetHostViewMac::AcceleratedSurfaceSuspend() {
+}
+
 void RenderWidgetHostViewMac::UpdateRootGpuViewVisibility(
     bool show_gpu_widget) {
   TRACE_EVENT1("renderer_host",
       "RenderWidgetHostViewMac::UpdateRootGpuViewVisibility",
       "show", show_gpu_widget);
   // Plugins are destroyed on page navigate. The compositor layer on the other
   // hand is created on demand and then stays alive until its renderer process
   // dies (usually on cross-domain navigation). Instead, only a flag
   // |is_accelerated_compositing_active()| is flipped when the compositor output
   // should be shown/hidden.
@@ skipping 1820 matching lines @@
   if (!string) return NO;
 
   // If the user is currently using an IME, confirm the IME input,
   // and then insert the text from the service, the same as TextEdit and Safari.
   [self confirmComposition];
   [self insertText:string];
   return YES;
 }
 
 @end