Make RendererGpuVideoDecoderFactories live on arbitrary threads.

media/filters/gpu_video_decoder.h

 // Copyright (c) 2012 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 MEDIA_FILTERS_GPU_VIDEO_DECODER_H_
 #define MEDIA_FILTERS_GPU_VIDEO_DECODER_H_
 
 #include <list>
 #include <map>
 #include <set>
@@ skipping 10 matching lines @@
 namespace base {
 class MessageLoopProxy;
 class SharedMemory;
 }
 
 class SkBitmap;
 
 namespace media {
 
 class DecoderBuffer;
-class VDAClientProxy;
 
 // GPU-accelerated video decoder implementation.  Relies on
 // AcceleratedVideoDecoderMsg_Decode and friends.
-// All methods internally trampoline to the |message_loop| passed to the ctor.
 class MEDIA_EXPORT GpuVideoDecoder
     : public VideoDecoder,
       public VideoDecodeAccelerator::Client {
  public:
   // Helper interface for specifying factories needed to instantiate a
   // GpuVideoDecoder.
   class MEDIA_EXPORT Factories : public base::RefCountedThreadSafe<Factories> {
    public:
     // Caller owns returned pointer.
     virtual VideoDecodeAccelerator* CreateVideoDecodeAccelerator(
@@ skipping 24 matching lines @@
     virtual void Abort() = 0;
 
     // Returns true if Abort() has been called.
     virtual bool IsAborted() = 0;
 
    protected:
     friend class base::RefCountedThreadSafe<Factories>;
     virtual ~Factories();
   };
 
-  GpuVideoDecoder(const scoped_refptr<base::MessageLoopProxy>& message_loop,

[scherkus (not reviewing), 2013/07/18 00:54:43]

this is a bit backwards ... for media::VideoDecoder implementations we pass in
the MLP of the thread that the media::VideoDecoder API is expected to run on

I'd revert this change and add a DCHECK() that message_loop ==
factories->GetMessageLoop() inside the ctor + update comment here

at least that way we'll require that |factories| must have been created to work
on the media message loop, and not the other way around (i.e., that
|factories|'s message loop just happens to be the right message loop for
media::VideoDecoder calls)


ideally GetMessageLoop() should go away entirely as I introduced as a temporary
measure since webkit/ code couldn't access content/, but that's no longer the
case, but it seems it has grown new use cases :(

https://codereview.chromium.org/11468033/diff/2001/media/filters/gpu_video_de...

[wuchengli, 2013/07/18 09:42:00]

Done. I added DCHECK. GetMessageLoop() are only used by DCHECK now. So it's not
too bad.

-                  const scoped_refptr<Factories>& factories);
+  GpuVideoDecoder(const scoped_refptr<Factories>& factories);
 
   // VideoDecoder implementation.
   virtual void Initialize(const VideoDecoderConfig& config,
                           const PipelineStatusCB& status_cb) OVERRIDE;
   virtual void Decode(const scoped_refptr<DecoderBuffer>& buffer,
                       const ReadCB& read_cb) OVERRIDE;
   virtual void Reset(const base::Closure& closure) OVERRIDE;
   virtual void Stop(const base::Closure& closure) OVERRIDE;
   virtual bool HasAlpha() const OVERRIDE;
   virtual bool NeedsBitstreamConversion() const OVERRIDE;
@@ skipping 34 matching lines @@
       const scoped_refptr<VideoFrame>& frame);
 
   // Indicate the picture buffer can be reused by the decoder.
   void ReusePictureBuffer(int64 picture_buffer_id, uint32 sync_point);
 
   void RecordBufferData(
       const BitstreamBuffer& bitstream_buffer, const DecoderBuffer& buffer);
   void GetBufferData(int32 id, base::TimeDelta* timetamp,
                      gfx::Rect* visible_rect, gfx::Size* natural_size);
 
-  // Sets |vda_| and |weak_vda_| on the GVD thread and runs |status_cb|.
-  void SetVDA(const PipelineStatusCB& status_cb,
-              VideoDecodeAccelerator* vda,
-              base::WeakPtr<VideoDecodeAccelerator> weak_vda);
-
-  // Call VDA::Destroy() on |vda_loop_proxy_| ensuring that |this| outlives the
-  // Destroy() call.
   void DestroyVDA();
 
   // A shared memory segment and its allocated size.
   struct SHMBuffer {
     SHMBuffer(base::SharedMemory* m, size_t s);
     ~SHMBuffer();
     base::SharedMemory* shm;
     size_t size;
   };
 
   // Request a shared-memory segment of at least |min_size| bytes.  Will
   // allocate as necessary.  Caller does not own returned pointer.
   SHMBuffer* GetSHM(size_t min_size);
 
   // Return a shared-memory segment to the available pool.
   void PutSHM(SHMBuffer* shm_buffer);
 
   void DestroyTextures();
 
   bool needs_bitstream_conversion_;
 
-  // Message loop on which to fire callbacks and trampoline calls to this class
-  // if they arrive on other loops.
+  // Message loop which this class and |factories_| run on.
   scoped_refptr<base::MessageLoopProxy> gvd_loop_proxy_;
   base::WeakPtrFactory<GpuVideoDecoder> weak_factory_;
   base::WeakPtr<GpuVideoDecoder> weak_this_;
 
-  // Message loop on which to makes all calls to vda_.  (beware this loop may be
-  // paused during the Pause/Flush/Stop dance PipelineImpl::Stop() goes
-  // through).
-  scoped_refptr<base::MessageLoopProxy> vda_loop_proxy_;
-
   scoped_refptr<Factories> factories_;
 
-  // Proxies calls from |vda_| to |gvd_loop_proxy_| and used to safely detach
-  // during shutdown.
-  scoped_refptr<VDAClientProxy> client_proxy_;
-
-  // Populated during Initialize() via SetVDA() (on success) and unchanged
-  // until an error occurs.
+  // Populated during Initialize() (on success) and unchanged until an error
+  // occurs.
   scoped_ptr<VideoDecodeAccelerator> vda_;
-  // Used to post tasks from the GVD thread to the VDA thread safely.
-  base::WeakPtr<VideoDecodeAccelerator> weak_vda_;
 
   // Callbacks that are !is_null() only during their respective operation being
   // asynchronously executed.
   ReadCB pending_read_cb_;
   base::Closure pending_reset_cb_;
 
   State state_;
 
   VideoDecoderConfig config_;
 
@@ skipping 43 matching lines @@
   // Set during ProvidePictureBuffers(), used for checking and implementing
   // HasAvailableOutputFrames().
   int available_pictures_;
 
   DISALLOW_COPY_AND_ASSIGN(GpuVideoDecoder);
 };
 
 }  // namespace media
 
 #endif  // MEDIA_FILTERS_GPU_VIDEO_DECODER_H_