Defer CGLFlushDrawable until OSX-requested drawRect to avoid spinning when window is obscured.

content/browser/renderer_host/render_widget_host_view_mac.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_BROWSER_RENDERER_HOST_RENDER_WIDGET_HOST_VIEW_MAC_H_
 #define CONTENT_BROWSER_RENDERER_HOST_RENDER_WIDGET_HOST_VIEW_MAC_H_
 #pragma once
 
 #import <Cocoa/Cocoa.h>
 #include <list>
@@ skipping 265 matching lines @@
       int32 height,
       TransportDIB::Handle transport_dib) OVERRIDE;
   virtual void AcceleratedSurfaceBuffersSwapped(
       const GpuHostMsg_AcceleratedSurfaceBuffersSwapped_Params& params,
       int gpu_host_id) OVERRIDE;
   virtual void AcceleratedSurfacePostSubBuffer(
       const GpuHostMsg_AcceleratedSurfacePostSubBuffer_Params& params,
       int gpu_host_id) OVERRIDE;
   virtual void AcceleratedSurfaceSuspend() OVERRIDE;
   virtual bool HasAcceleratedSurface(const gfx::Size& desired_size) OVERRIDE;
+  virtual void AboutToWaitForBackingStoreMsg() OVERRIDE;
   virtual void GetScreenInfo(WebKit::WebScreenInfo* results) OVERRIDE;
   virtual gfx::Rect GetRootWindowBounds() OVERRIDE;
   virtual gfx::GLSurfaceHandle GetCompositingSurface() OVERRIDE;
 
   void DrawAcceleratedSurfaceInstance(
       CGLContextObj context,
       gfx::PluginWindowHandle plugin_handle,
       NSSize size);
   // Forces the textures associated with any accelerated plugin instances
   // to be reloaded.
@@ skipping 16 matching lines @@
   void KillSelf();
 
   void SetTextInputActive(bool active);
 
   // Sends completed plugin IME notification and text back to the renderer.
   void PluginImeCompositionCompleted(const string16& text, int plugin_id);
 
   const std::string& selected_text() const { return selected_text_; }
 
   // Call setNeedsDisplay on the cocoa_view_. The IOSurface will be drawn during
-  // the next drawRect.
-  void CompositorSwapBuffers(uint64 surface_handle);
+  // the next drawRect. Return true if the Ack should be sent, false if it
+  // should be deferred until drawRect.
+  bool CompositorSwapBuffers(uint64 surface_handle);
+  // Ack pending SwapBuffers requests, if any, to unblock the GPU process. Has
+  // no effect if there are no pending requests.
+  void AckPendingSwapBuffers();
 
   // These member variables should be private, but the associated ObjC class
   // needs access to them and can't be made a friend.
 
   // The associated Model.  Can be NULL if Destroy() is called when
   // someone (other than superview) has retained |cocoa_view_|.
   content::RenderWidgetHostImpl* render_widget_host_;
 
   // This is true when we are currently painting and thus should handle extra
   // paint requests by expanding the invalid rect rather than actually painting.
@@ skipping 79 matching lines @@
   // Factory used to safely scope delayed calls to ShutdownHost().
   base::WeakPtrFactory<RenderWidgetHostViewMac> weak_factory_;
 
   // selected text on the renderer.
   std::string selected_text_;
 
   // The fullscreen window used for pepper flash.
   scoped_nsobject<NSWindow> pepper_fullscreen_window_;
   scoped_nsobject<FullscreenWindowManager> fullscreen_window_manager_;
 
+  // List of pending swaps for deferred acking:
+  //   pairs of (route_id, gpu_host_id).
+  std::list<std::pair<int32, int32> > pending_swap_buffers_acks_;
+
   DISALLOW_COPY_AND_ASSIGN(RenderWidgetHostViewMac);
 };
 
 #endif  // CONTENT_BROWSER_RENDERER_HOST_RENDER_WIDGET_HOST_VIEW_MAC_H_