Delete background tab IOSurfaces on Mac.

content/port/browser/render_widget_host_view_port.h

 // 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.
 
 #ifndef CONTENT_PORT_BROWSER_RENDER_WIDGET_HOST_VIEW_PORT_H_
 #define CONTENT_PORT_BROWSER_RENDER_WIDGET_HOST_VIEW_PORT_H_
 #pragma once
 
 #include "base/callback.h"
 #include "base/process_util.h"
@@ skipping 157 matching lines @@
   // Similar to above, except |params.(x|y|width|height)| define the region
   // of the surface that changed.
   virtual void AcceleratedSurfacePostSubBuffer(
       const GpuHostMsg_AcceleratedSurfacePostSubBuffer_Params& params,
       int gpu_host_id) = 0;
 
   // Release the accelerated surface temporarily. It will be recreated on the
   // next swap buffers or post sub buffer.
   virtual void AcceleratedSurfaceSuspend() = 0;
 
+  // Return true if the view has an accelerated surface that contains the last
+  // presented frame for the view. If |desired_size| is non-empty, true is
+  // returned only if the accelerated surface size matches.
+  virtual bool HasAcceleratedSurface(const gfx::Size& desired_size) = 0;
+
 #if defined(OS_MACOSX)
   // Retrieve the bounds of the view, in cocoa view coordinates.
   // If the UI scale factor is 2, |GetViewBounds()| will return a size of e.g.
   // (400, 300) in pixels, while this method will return (200, 150).
   // Even though this returns an gfx::Rect, the result is NOT IN PIXELS.
   virtual gfx::Rect GetViewCocoaBounds() const = 0;
 
   // Informs the view that a plugin gained or lost focus.
   virtual void PluginFocusChanged(bool focused, int plugin_id) = 0;
 
@@ skipping 71 matching lines @@
   virtual BrowserAccessibilityManager*
       GetBrowserAccessibilityManager() const = 0;
   virtual void OnAccessibilityNotifications(
       const std::vector<AccessibilityHostMsg_NotificationParams>& params) {
   }
 };
 
 }  // namespace content
 
 #endif  // CONTENT_PORT_BROWSER_RENDER_WIDGET_HOST_VIEW_PORT_H_