Use enum instead of string in MessageLoopFactory::GetMessageLoop*

content/renderer/media/renderer_gpu_video_decoder_factories.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_MEDIA_RENDERER_GPU_VIDEO_DECODER_FACTORIES_H_
 #define CONTENT_RENDERER_MEDIA_RENDERER_GPU_VIDEO_DECODER_FACTORIES_H_
 
 #include "base/basictypes.h"
 #include "base/memory/ref_counted.h"
 #include "base/memory/weak_ptr.h"
@@ skipping 18 matching lines @@
 // the constructor-argument loop (mostly that's the compositor thread, or the
 // renderer thread if threaded compositing is disabled), and shmem-related calls
 // go to the render thread.
 class CONTENT_EXPORT RendererGpuVideoDecoderFactories
     : public media::GpuVideoDecoder::Factories {
  public:
   // Takes a ref on |gpu_channel_host| and tests |context| for NULL before each
   // use.
   RendererGpuVideoDecoderFactories(
       GpuChannelHost* gpu_channel_host,
-      MessageLoop* message_loop,
+      const scoped_refptr<base::MessageLoopProxy>& message_loop,
       const base::WeakPtr<WebGraphicsContext3DCommandBufferImpl>& wgc3dcbi);
 
   virtual media::VideoDecodeAccelerator* CreateVideoDecodeAccelerator(
       media::VideoCodecProfile profile,
       media::VideoDecodeAccelerator::Client* client) OVERRIDE;
 
   virtual bool CreateTextures(int32 count, const gfx::Size& size,
                               std::vector<uint32>* texture_ids,
                               uint32 texture_target) OVERRIDE;
 
@@ skipping 20 matching lines @@
       media::VideoDecodeAccelerator::Client* client,
       media::VideoDecodeAccelerator** vda,
       base::WaitableEvent* waiter);
   void AsyncCreateTextures(
       int32 count, const gfx::Size& size, std::vector<uint32>* texture_ids,
       uint32 texture_target, bool* success, base::WaitableEvent* waiter);
   void AsyncDeleteTexture(uint32 texture_id);
   void AsyncCreateSharedMemory(
       size_t size, base::SharedMemory** shm, base::WaitableEvent* waiter);
 
-  MessageLoop* message_loop_;
+  scoped_refptr<base::MessageLoopProxy> message_loop_;
   scoped_refptr<GpuChannelHost> gpu_channel_host_;
   base::WeakPtr<WebGraphicsContext3DCommandBufferImpl> context_;
   DISALLOW_IMPLICIT_CONSTRUCTORS(RendererGpuVideoDecoderFactories);
 };
 
 #endif  // CONTENT_RENDERER_MEDIA_RENDERER_GPU_VIDEO_DECODER_FACTORIES_H_