Remove the MessageLoop::DestructionObserver from mojo bindings.

content/browser/gpu/browser_gpu_channel_host_factory.h

Index: content/browser/gpu/browser_gpu_channel_host_factory.h
diff --git a/content/browser/gpu/browser_gpu_channel_host_factory.h b/content/browser/gpu/browser_gpu_channel_host_factory.h
index c01f04eab3469dddc0a197c228644e671ae827fd..c1388b7c58d54a6e60cd70ac6600f1eab228e0b3 100644
--- a/content/browser/gpu/browser_gpu_channel_host_factory.h
+++ b/content/browser/gpu/browser_gpu_channel_host_factory.h
@@ -40,6 +40,10 @@ class CONTENT_EXPORT BrowserGpuChannelHostFactory
   gpu::GpuChannelHost* GetGpuChannel();
   int GetGpuChannelId() { return gpu_client_id_; }
 
+  // Closes the channel to the GPU process. This should be called before the IO
+  // thread stops.
+  void CloseChannel();
+
   // Used to skip GpuChannelHost tests when there can be no GPU process.
   static bool CanUseForTesting();