Make RendererGpuVideoDecoderFactories live on arbitrary threads.

content/renderer/media/rtc_video_decoder.h

 // Copyright 2013 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #ifndef CONTENT_RENDERER_MEDIA_RTC_VIDEO_DECODER_H_
 #define CONTENT_RENDERER_MEDIA_RTC_VIDEO_DECODER_H_
 
 #include <deque>
 #include <set>
 #include <utility>
@@ skipping 17 matching lines @@
 class MessageLoopProxy;
 };
 
 namespace media {
 class DecoderBuffer;
 }
 
 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
+// WebRTC. |vda_message_loop_| is the message loop proxy of the media thread,
+// which VDA::Client methods run on. 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_|.
+// frames are delivered to WebRTC on |vda_message_loop_|.
 class CONTENT_EXPORT RTCVideoDecoder
     : NON_EXPORTED_BASE(public webrtc::VideoDecoder),
       public media::VideoDecodeAccelerator::Client,
       public base::MessageLoop::DestructionObserver {
  public:
   virtual ~RTCVideoDecoder();
 
-  // Creates a RTCVideoDecoder. Returns NULL if failed.
+  // Creates a RTCVideoDecoder. Returns NULL if failed. |vda_loop_proxy| should
+  // be the same as the one running |factories|.
   static scoped_ptr<RTCVideoDecoder> Create(
+      webrtc::VideoCodecType type,
+      const scoped_refptr<base::MessageLoopProxy> vda_loop_proxy,
       const scoped_refptr<media::GpuVideoDecoder::Factories>& factories);
 
   // webrtc::VideoDecoder implementation.
   // Called on WebRTC DecodingThread.
   virtual int32_t InitDecode(const webrtc::VideoCodec* codecSettings,
                              int32_t numberOfCores) OVERRIDE;
   // Called on WebRTC DecodingThread.
   virtual int32_t Decode(
       const webrtc::EncodedImage& inputImage,
       bool missingFrames,
@@ skipping 39 matching lines @@
     ~BufferData();
     int32 bitstream_buffer_id;
     uint32_t timestamp;  // in 90KHz
     uint32_t width;
     uint32_t height;
     size_t size;  // buffer size
   };
 
   FRIEND_TEST_ALL_PREFIXES(RTCVideoDecoderTest, IsBufferAfterReset);
 
+  // |vda_loop_proxy| should be the same as the one running |factories|.
   RTCVideoDecoder(
+      const scoped_refptr<base::MessageLoopProxy>& vda_loop_proxy,
       const scoped_refptr<media::GpuVideoDecoder::Factories>& factories);
 
   void Initialize(base::WaitableEvent* waiter);
 
   // Requests a buffer to be decoded by VDA.
   void RequestBufferDecode();
 
   bool CanMoreDecodeWorkBeDone();
 
   // Returns true if bitstream buffer id |id_buffer| comes after |id_reset|.
@@ skipping 16 matching lines @@
   scoped_refptr<media::VideoFrame> CreateVideoFrame(
       const media::Picture& picture,
       const media::PictureBuffer& pb,
       uint32_t timestamp,
       uint32_t width,
       uint32_t height,
       size_t size);
 
   // Resets VDA.
   void ResetInternal();
+  void ReleaseInternal();
 
   // Tells VDA that a picture buffer can be recycled.
   void ReusePictureBuffer(int64 picture_buffer_id, uint32 sync_point);
 
   void DestroyTextures();
   void DestroyVDA();
 
   // Gets a shared-memory segment of at least |min_size| bytes from
   // |available_shm_segments_|. Returns NULL if there is no buffer or the
   // buffer is not big enough.
@@ skipping 34 matching lines @@
   // The weak pointer should live and die on the |vda_loop_proxy_|;
   base::WeakPtrFactory<RTCVideoDecoder> weak_factory_;
   base::WeakPtr<RTCVideoDecoder> weak_this_;
 
   scoped_refptr<media::GpuVideoDecoder::Factories> factories_;
 
   // The message loop to run callbacks on. This is should be the same as the one
   // 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_;
 
   // Metadata of the buffers that have been sent for decode.
   std::list<BufferData> input_buffer_data_;
 
   // A map from bitstream buffer IDs to bitstream buffers that are being
   // processed by VDA. The map owns SHM buffers.
   std::map<int32, SHMBuffer*> bitstream_buffers_in_decoder_;
 
@@ skipping 45 matching lines @@
   // A buffer that has an id less than this should be dropped because Reset or
   // Release has been called. Guarded by |lock_|.
   int32 reset_bitstream_buffer_id_;
 
   DISALLOW_COPY_AND_ASSIGN(RTCVideoDecoder);
 };
 
 }  // namespace content
 
 #endif  // CONTENT_RENDERER_MEDIA_RTC_VIDEO_DECODER_H_