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

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 158 matching lines @@
 
   // 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;
 
+  // Called just before GetBackingStore blocks for an updated frame.
+  virtual void AboutToWaitForBackingStoreMsg() {}

[Jói, 2012/05/18 07:28:27]

I'd prefer to leave this pure virtual like all the other methods.  Should this
be within the #if defined(OS_MACOSX) block since you only implement it for Mac?

[jbates, 2012/05/21 22:41:59]

Done.

+
 #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_