Defer render_widget draw until host window is available

content/renderer/render_view_impl.h

Index: content/renderer/render_view_impl.h
diff --git a/content/renderer/render_view_impl.h b/content/renderer/render_view_impl.h
index 6c60ae33157055cf569cce2545ec1a7d30dbb37d..63a5a374b31d3cb624ef2820dadc1cf8bf3a69a4 100644
--- a/content/renderer/render_view_impl.h
+++ b/content/renderer/render_view_impl.h
@@ -1136,6 +1136,13 @@ class RenderViewImpl : public RenderWidget,
   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_;