Android: Avoid blocking UI thread for GPU channel creation

content/browser/renderer_host/compositor_impl_android.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_COMPOSITOR_IMPL_ANDROID_H_
 #define CONTENT_BROWSER_RENDERER_HOST_COMPOSITOR_IMPL_ANDROID_H_
 
 #include "base/basictypes.h"
 #include "base/compiler_specific.h"
 #include "base/containers/scoped_ptr_hash_map.h"
 #include "base/memory/scoped_ptr.h"
+#include "base/memory/weak_ptr.h"
 #include "cc/resources/ui_resource_client.h"
 #include "cc/trees/layer_tree_host_client.h"
 #include "cc/trees/layer_tree_host_single_thread_client.h"
 #include "content/browser/renderer_host/image_transport_factory_android.h"
 #include "content/common/content_export.h"
 #include "content/public/browser/android/compositor.h"
 #include "third_party/khronos/GLES2/gl2.h"
 #include "ui/base/android/window_android_compositor.h"
 
 class SkBitmap;
@@ skipping 76 matching lines @@
   // ImageTransportFactoryAndroidObserver implementation.
   virtual void OnLostResources() OVERRIDE;
 
   // WindowAndroidCompositor implementation.
   virtual void AttachLayerForReadback(scoped_refptr<cc::Layer> layer) OVERRIDE;
 
  private:
   cc::UIResourceId GenerateUIResourceFromUIResourceBitmap(
       const cc::UIResourceBitmap& bitmap,
       bool is_transient);
+  void OnGpuChannelEstablished();
 
   scoped_refptr<cc::Layer> root_layer_;
   scoped_ptr<cc::LayerTreeHost> host_;
 
   gfx::Size size_;
   bool has_transparent_background_;
   float device_scale_factor_;
 
   ANativeWindow* window_;
   int surface_id_;
 
   CompositorClient* client_;
 
   scoped_refptr<cc::ContextProvider> null_offscreen_context_provider_;
 
   typedef base::ScopedPtrHashMap<cc::UIResourceId, cc::UIResourceClient>
       UIResourceMap;
   UIResourceMap ui_resource_map_;
 
   gfx::NativeWindow root_window_;
+  base::WeakPtrFactory<CompositorImpl> weak_factory_;
 
   DISALLOW_COPY_AND_ASSIGN(CompositorImpl);
 };
 
 } // namespace content
 
 #endif  // CONTENT_BROWSER_RENDERER_HOST_COMPOSITOR_IMPL_ANDROID_H_