Implement proper synchronization between HW video decode IPC and CommandBuffer.

content/common/gpu/gpu_channel.h

Index: content/common/gpu/gpu_channel.h
diff --git a/content/common/gpu/gpu_channel.h b/content/common/gpu/gpu_channel.h
index 6c57a295dcf025f719d168147f259df47bc46ac9..8477b9204494545c30f0e72241f5e224a21cfdd5 100644
--- a/content/common/gpu/gpu_channel.h
+++ b/content/common/gpu/gpu_channel.h
@@ -151,11 +151,6 @@ class GpuChannel : public IPC::Channel::Listener,
   void OnDestroyVideoDecoder(int32 decoder_id);
   void OnCreateTransportTexture(int32 context_route_id, int32 host_id);
 
-  void OnAssignTexturesToVideoDecoder(int32 decoder_id,
-                                      const std::vector<int32>& buffer_ids,
-                                      const std::vector<uint32>& texture_ids,
-                                      const std::vector<gfx::Size>& sizes);
-
   // The lifetime of objects of this class is managed by a GpuChannelManager.
   // The GpuChannelManager destroy all the GpuChannels that they own when they
   // are destroyed. So a raw pointer is safe.