Allow multiple concurrent Decode() requests in VideoDecoder interface.

media/filters/gpu_video_decoder.h

Index: media/filters/gpu_video_decoder.h
diff --git a/media/filters/gpu_video_decoder.h b/media/filters/gpu_video_decoder.h
index e8f5f756facf1162f7dfce94e97b47c78555c44d..53cc153eafeb0e873ffe45b417ef5350a3104ed0 100644
--- a/media/filters/gpu_video_decoder.h
+++ b/media/filters/gpu_video_decoder.h
@@ -50,6 +50,7 @@ class MEDIA_EXPORT GpuVideoDecoder
   virtual void Stop() OVERRIDE;
   virtual bool NeedsBitstreamConversion() const OVERRIDE;
   virtual bool CanReadWithoutStalling() const OVERRIDE;
+  virtual int GetMaxDecodeRequests() const OVERRIDE;
 
   // VideoDecodeAccelerator::Client implementation.
   virtual void ProvidePictureBuffers(uint32 count,
@@ -91,16 +92,7 @@ class MEDIA_EXPORT GpuVideoDecoder
 
   typedef std::map<int32, PictureBuffer> PictureBufferMap;
 
-  // Return true if more decode work can be piled on to the VDA.
-  bool CanMoreDecodeWorkBeDone();
-
-  // Enqueue a frame for later delivery (or drop it on the floor if a
-  // vda->Reset() is in progress) and trigger out-of-line delivery of the oldest
-  // ready frame to the client if there is a pending read.  A NULL |frame|
-  // merely triggers delivery, and requires the ready_video_frames_ queue not be
-  // empty.
-  void EnqueueFrameAndTriggerFrameDelivery(
-      const scoped_refptr<VideoFrame>& frame);
+  void DeliverFrame( const scoped_refptr<VideoFrame>& frame);
 
   // Static method is to allow it to run even after GVD is deleted.
   static void ReleaseMailbox(
@@ -140,9 +132,11 @@ class MEDIA_EXPORT GpuVideoDecoder
   // occurs.
   scoped_ptr<VideoDecodeAccelerator> vda_;
 
-  // Callbacks that are !is_null() only during their respective operation being
-  // asynchronously executed.
-  DecodeCB pending_decode_cb_;
+  // Callbacks for the pending Decode requests (not more than
+  // GetMaxDecodeRequests()).
+  std::list<DecodeCB> pending_decode_callbacks_;
+
+  // Not null only during reset.
   base::Closure pending_reset_cb_;
 
   State state_;
@@ -181,7 +175,6 @@ class MEDIA_EXPORT GpuVideoDecoder
 
   // picture_buffer_id and the frame wrapping the corresponding Picture, for
   // frames that have been decoded but haven't been requested by a Decode() yet.
-  std::list<scoped_refptr<VideoFrame> > ready_video_frames_;
   int32 next_picture_buffer_id_;
   int32 next_bitstream_buffer_id_;