Adds locks for CommandBufferProxyImpl invalidation

media/gpu/ipc/client/gpu_video_decode_accelerator_host.h

Index: media/gpu/ipc/client/gpu_video_decode_accelerator_host.h
diff --git a/media/gpu/ipc/client/gpu_video_decode_accelerator_host.h b/media/gpu/ipc/client/gpu_video_decode_accelerator_host.h
index 2ba09634b483b851cc02029ad6e4a12cc3ccd76c..f3c8cac507c3fa978ce690132ada35ff02ec9235 100644
--- a/media/gpu/ipc/client/gpu_video_decode_accelerator_host.h
+++ b/media/gpu/ipc/client/gpu_video_decode_accelerator_host.h
@@ -80,12 +80,19 @@ class GpuVideoDecodeAcceleratorHost
 
   scoped_refptr<gpu::GpuChannelHost> channel_;
 
+  // Callback to a function that releases |channel_|.
+  base::Callback<void(void)> channel_error_cb_;
+
   // Route ID for the associated decoder in the GPU process.
   int32_t decoder_route_id_;
 
   // The client that will receive callbacks from the decoder.
   Client* client_;
 
+  // Protect |impl_|. |impl_| is used on media thread, but it can be invalidated
+  // on main thread.
+  base::Lock impl_lock_;
+
   // Unowned reference to the gpu::CommandBufferProxyImpl that created us.
   // |this| registers as a DeletionObserver of |impl_|, the so reference is
   // always valid as long as it is not NULL.