Make RendererGpuVideoDecoderFactories live on arbitrary threads.

content/renderer/media/rtc_video_decoder.h

Index: content/renderer/media/rtc_video_decoder.h
diff --git a/content/renderer/media/rtc_video_decoder.h b/content/renderer/media/rtc_video_decoder.h
index 8c4c195fe1302b86914e52fc7956959ee03bb63a..619c632523da51e472db7c702e7b63deb8f3ee2e 100644
--- a/content/renderer/media/rtc_video_decoder.h
+++ b/content/renderer/media/rtc_video_decoder.h
@@ -36,12 +36,11 @@ namespace content {
 
 // This class uses hardware accelerated video decoder to decode video for
 // WebRTC. The message loop of RendererGpuVideoDecoderFactories is stored as
-// |vda_message_loop_|. It is the compositor thread, or the renderer thread if
-// threaded compositing is disabled. VDA::Client methods run on
-// |vda_message_loop_|. webrtc::VideoDecoder methods run on WebRTC
-// DecodingThread or Chrome_libJingle_WorkerThread, which are trampolined to
-// |vda_message_loop_|. Decode() is non-blocking and queues the buffers. Decoded
-// frames are delivered on |vda_message_loop_|.
+// |vda_message_loop_|. VDA::Client methods run on |vda_message_loop_|.
+// webrtc::VideoDecoder methods run on WebRTC DecodingThread or
+// Chrome_libJingle_WorkerThread, which are trampolined to |vda_message_loop_|.
+// Decode() is non-blocking and queues the buffers. Decoded frames are delivered
+// on |vda_message_loop_|.
 class CONTENT_EXPORT RTCVideoDecoder
     : NON_EXPORTED_BASE(public webrtc::VideoDecoder),
       public media::VideoDecodeAccelerator::Client,
@@ -51,6 +50,7 @@ class CONTENT_EXPORT RTCVideoDecoder
 
   // Creates a RTCVideoDecoder. Returns NULL if failed.
   static scoped_ptr<RTCVideoDecoder> Create(
+      webrtc::VideoCodecType type,
       const scoped_refptr<media::GpuVideoDecoder::Factories>& factories);
 
   // webrtc::VideoDecoder implementation.
@@ -147,6 +147,7 @@ class CONTENT_EXPORT RTCVideoDecoder
 
   // Resets VDA.
   void ResetInternal();
+  void ReleaseInternal();
 
   // Tells VDA that a picture buffer can be recycled.
   void ReusePictureBuffer(int64 picture_buffer_id, uint32 sync_point);
@@ -201,15 +202,6 @@ class CONTENT_EXPORT RTCVideoDecoder
   // of |factories_|.
   scoped_refptr<base::MessageLoopProxy> vda_loop_proxy_;
 
-  // The thread to create shared memory. Factories::CreateSharedMemory is
-  // trampolined to the child thread. When |vda_loop_proxy_| is the compositor
-  // thread, blocking on the child thread will deadlock. During WebRTC hang up,
-  // the child thread waits for Chrome_libJingle_WorkerThread. libJingle thread
-  // cannot finish when DecodingThread holds a WebRTC lock and blocks on the
-  // child thread. So we need to call CreateSharedMemory asynchronously from a
-  // different thread.
-  base::Thread create_shm_thread_;
-
   // The texture target used for decoded pictures.
   uint32 decoder_texture_target_;