Defer render_widget draw until host window is available

content/renderer/render_view_impl.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_RENDERER_RENDER_VIEW_IMPL_H_
 #define CONTENT_RENDERER_RENDER_VIEW_IMPL_H_
 #pragma once
 
 #include <deque>
 #include <map>
@@ skipping 1117 matching lines @@
   bool cached_has_main_frame_horizontal_scrollbar_;
   bool cached_has_main_frame_vertical_scrollbar_;
 
 #if defined(OS_MACOSX)
   // Track the fake plugin window handles allocated on the browser side for
   // the accelerated compositor and (currently) accelerated plugins so that
   // we can discard them when the view goes away.
   std::set<gfx::PluginWindowHandle> fake_plugin_window_handles_;
 #endif
 
+  // When this view is composited, the context used for compositing may or may
+  // not support the GL_CHROMIUM_swapbuffers_complete_callback extension. Since
+  // querying for the existence of this extension is expensive we cache the
+  // result. These are used to implement SupportsAsynchronousSwapBuffers().
+  bool context_has_swapbuffers_complete_callback_;
+  bool queried_for_swapbuffers_complete_callback_;
+
   // Helper objects ------------------------------------------------------------
 
   RendererWebCookieJarImpl cookie_jar_;
 
   // The next group of objects all implement RenderViewObserver, so are deleted
   // along with the RenderView automatically.  This is why we just store
   // weak references.
 
   // Holds a reference to the service which provides desktop notifications.
   NotificationProvider* notification_provider_;
@@ skipping 112 matching lines @@
   // bunch of stuff, you should probably create a helper class and put your
   // data and methods on that to avoid bloating RenderView more.  You can
   // use the Observer interface to filter IPC messages and receive frame change
   // notifications.
   // ---------------------------------------------------------------------------
 
   DISALLOW_COPY_AND_ASSIGN(RenderViewImpl);
 };
 
 #endif  // CONTENT_RENDERER_RENDER_VIEW_IMPL_H_