Make RendererGpuVideoDecoderFactories live on arbitrary threads.

content/renderer/render_thread_impl.h

Index: content/renderer/render_thread_impl.h
diff --git a/content/renderer/render_thread_impl.h b/content/renderer/render_thread_impl.h
index cd95d44f341bd81c2c19b4bb6df55c54ca14baa0..5b3dac04b9a03cd7994a8ec7ec7e17b2afb65a7d 100644
--- a/content/renderer/render_thread_impl.h
+++ b/content/renderer/render_thread_impl.h
@@ -19,6 +19,7 @@
 #include "content/common/gpu/client/gpu_channel_host.h"
 #include "content/common/gpu/gpu_process_launch_causes.h"
 #include "content/public/renderer/render_thread.h"
+#include "content/renderer/media/renderer_gpu_video_decoder_factories.h"
 #include "ipc/ipc_channel_proxy.h"
 #include "ui/gfx/native_widget_types.h"
 
@@ -255,9 +256,10 @@ class CONTENT_EXPORT RenderThreadImpl : public RenderThread,
   // not sent for at least one notification delay.
   void PostponeIdleNotification();
 
-  // Gets gpu factories. Returns NULL if VDA is disabled or a graphics context
-  // cannot be obtained.
-  scoped_refptr<media::GpuVideoDecoderFactories> GetGpuFactories();
+  // Gets gpu factories, which will run on |factories_loop|. Returns NULL if VDA
+  // is disabled or a graphics context cannot be obtained.
+  scoped_refptr<RendererGpuVideoDecoderFactories> GetGpuFactories(
+      const scoped_refptr<base::MessageLoopProxy>& factories_loop);
 
   // Returns a graphics context shared among all
   // RendererGpuVideoDecoderFactories, or NULL on error.  Context remains owned