Fix lifecycle-vs-threads of GpuVDAContext3D.

content/renderer/media/renderer_gpu_video_decoder_factories.h

Index: content/renderer/media/renderer_gpu_video_decoder_factories.h
diff --git a/content/renderer/media/renderer_gpu_video_decoder_factories.h b/content/renderer/media/renderer_gpu_video_decoder_factories.h
index 367dcb9faf0c10ca9985540986cb23c5ced9df38..7385a10f67de1c5b6aadb28aab6a22882cc7ea88 100644
--- a/content/renderer/media/renderer_gpu_video_decoder_factories.h
+++ b/content/renderer/media/renderer_gpu_video_decoder_factories.h
@@ -32,12 +32,12 @@ class WaitableEvent;
 class CONTENT_EXPORT RendererGpuVideoDecoderFactories
     : public media::GpuVideoDecoder::Factories {
  public:
-  // Takes a ref on |gpu_channel_host| and tests |context| for NULL before each
+  // Takes a ref on |gpu_channel_host| and tests |context| for loss before each
   // use.
   RendererGpuVideoDecoderFactories(
       GpuChannelHost* gpu_channel_host,
       MessageLoop* message_loop,
-      const base::WeakPtr<WebGraphicsContext3DCommandBufferImpl>& wgc3dcbi);
+      WebGraphicsContext3DCommandBufferImpl* wgc3dcbi);
 
   virtual media::VideoDecodeAccelerator* CreateVideoDecodeAccelerator(
       media::VideoCodecProfile profile,
@@ -58,7 +58,8 @@ class CONTENT_EXPORT RendererGpuVideoDecoderFactories
  private:
   // Helper for the constructor to acquire the ContentGLContext on the
   // compositor thread (when it is enabled).
-  void AsyncGetContext(base::WaitableEvent* waiter);
+  void AsyncGetContext(WebGraphicsContext3DCommandBufferImpl* context,
+                       base::WaitableEvent* waiter);
 
   // Async versions of the public methods.  They use output parameters instead
   // of return values and each takes a WaitableEvent* param to signal completion