Revert r180578, r180591, and r180604 from 1410 branch.

media/filters/video_renderer_base.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_VIDEO_RENDERER_BASE_H_
 #define MEDIA_FILTERS_VIDEO_RENDERER_BASE_H_
 
 #include <deque>
 
 #include "base/memory/ref_counted.h"
-#include "base/memory/weak_ptr.h"
 #include "base/synchronization/condition_variable.h"
 #include "base/synchronization/lock.h"
 #include "base/threading/platform_thread.h"
 #include "media/base/decryptor.h"
 #include "media/base/demuxer_stream.h"
 #include "media/base/pipeline_status.h"
 #include "media/base/video_decoder.h"
 #include "media/base/video_frame.h"
 #include "media/base/video_renderer.h"
 
 namespace base {
 class MessageLoopProxy;
 }
 
 namespace media {
 
 class DecryptingDemuxerStream;
 class VideoDecoderSelector;
 
 // VideoRendererBase creates its own thread for the sole purpose of timing frame
 // presentation.  It handles reading from the decoder and stores the results in
 // a queue of decoded frames and executing a callback when a frame is ready for
 // rendering.
 class MEDIA_EXPORT VideoRendererBase
     : public VideoRenderer,
       public base::PlatformThread::Delegate {
  public:
-  typedef base::Callback<void(const scoped_refptr<VideoFrame>&)> PaintCB;
   typedef base::Callback<void(bool)> SetOpaqueCB;
 
   // Maximum duration of the last frame.
   static base::TimeDelta kMaxLastFrameDuration();
 
   // |paint_cb| is executed on the video frame timing thread whenever a new
-  // frame is available for painting.
+  // frame is available for painting via GetCurrentFrame().
   //
   // |set_opaque_cb| is executed when the renderer is initialized to inform
   // the player whether the decoder's output will be opaque or not.
   //
   // Implementors should avoid doing any sort of heavy work in this method and
   // instead post a task to a common/worker thread to handle rendering.  Slowing
   // down the video thread may result in losing synchronization with audio.
   //
   // Setting |drop_frames_| to true causes the renderer to drop expired frames.
   //
   // TODO(scherkus): pass the VideoFrame* to this callback and remove
   // Get/PutCurrentFrame() http://crbug.com/108435
   VideoRendererBase(const scoped_refptr<base::MessageLoopProxy>& message_loop,
                     const SetDecryptorReadyCB& set_decryptor_ready_cb,
-                    const PaintCB& paint_cb,
+                    const base::Closure& paint_cb,
                     const SetOpaqueCB& set_opaque_cb,
                     bool drop_frames);
-  virtual ~VideoRendererBase();
 
   // VideoRenderer implementation.
   virtual void Initialize(const scoped_refptr<DemuxerStream>& stream,
                           const VideoDecoderList& decoders,
                           const PipelineStatusCB& init_cb,
                           const StatisticsCB& statistics_cb,
                           const TimeCB& max_time_cb,
                           const NaturalSizeChangedCB& size_changed_cb,
                           const base::Closure& ended_cb,
                           const PipelineStatusCB& error_cb,
                           const TimeDeltaCB& get_time_cb,
                           const TimeDeltaCB& get_duration_cb) OVERRIDE;
   virtual void Play(const base::Closure& callback) OVERRIDE;
   virtual void Pause(const base::Closure& callback) OVERRIDE;
   virtual void Flush(const base::Closure& callback) OVERRIDE;
   virtual void Preroll(base::TimeDelta time,
                        const PipelineStatusCB& cb) OVERRIDE;
   virtual void Stop(const base::Closure& callback) OVERRIDE;
   virtual void SetPlaybackRate(float playback_rate) OVERRIDE;
 
   // PlatformThread::Delegate implementation.
   virtual void ThreadMain() OVERRIDE;
 
+  // Clients of this class (painter/compositor) should use GetCurrentFrame()
+  // obtain ownership of VideoFrame, it should always relinquish the ownership
+  // by use PutCurrentFrame(). Current frame is not guaranteed to be non-NULL.
+  // It expects clients to use color-fill the background if current frame
+  // is NULL. This could happen before pipeline is pre-rolled or during
+  // pause/flush/preroll.
+  void GetCurrentFrame(scoped_refptr<VideoFrame>* frame_out);
+  void PutCurrentFrame(scoped_refptr<VideoFrame> frame);
+
+ protected:
+  virtual ~VideoRendererBase();
+
  private:
   // Called when |decoder_selector_| selected the |selected_decoder|.
   // |decrypting_demuxer_stream| was also populated if a DecryptingDemuxerStream
   // created to help decrypt the encrypted stream.
   // Note: |decoder_selector| is passed here to keep the VideoDecoderSelector
   // alive until OnDecoderSelected() finishes.
   void OnDecoderSelected(
       scoped_ptr<VideoDecoderSelector> decoder_selector,
       const scoped_refptr<VideoDecoder>& selected_decoder,
       const scoped_refptr<DecryptingDemuxerStream>& decrypting_demuxer_stream);
@@ skipping 10 matching lines @@
   // as there isn't a pending read and we have capacity.
   void AttemptRead();
   void AttemptRead_Locked();
 
   // Called when VideoDecoder::Reset() completes.
   void OnDecoderResetDone();
 
   // Attempts to complete flushing and transition into the flushed state.
   void AttemptFlush_Locked();
 
-  // Calculates the duration to sleep for based on |last_timestamp_|,
+  // Calculates the duration to sleep for based on |current_frame_|'s timestamp,
   // the next frame timestamp (may be NULL), and the provided playback rate.
   //
   // We don't use |playback_rate_| to avoid locking.
   base::TimeDelta CalculateSleepDuration(
       const scoped_refptr<VideoFrame>& next_frame,
       float playback_rate);
 
   // Helper function that flushes the buffers when a Stop() or error occurs.
   void DoStopOrError_Locked();
 
   // Return the number of frames currently held by this class.
   int NumFrames_Locked() const;
 
-  // Runs |paint_cb_| with the next frame from |ready_frames_|, updating
-  // |last_natural_size_| and running |size_changed_cb_| if the natural size
-  // changes.
-  //
-  // A read is scheduled to replace the frame.
-  void PaintNextReadyFrame_Locked();
-
-  // Drops the next frame from |ready_frames_| and runs |statistics_cb_|.
-  //
-  // A read is scheduled to replace the frame.
-  void DropNextReadyFrame_Locked();
+  // Updates |current_frame_| to the next frame on |ready_frames_| and calls
+  // |size_changed_cb_| if the natural size changes.
+  void SetCurrentFrameToNextReadyFrame();
 
   void ResetDecoder();
   void StopDecoder(const base::Closure& callback);
 
   // Pops the front of |decoders|, assigns it to |decoder_| and then
   // calls initialize on the new decoder.
   void InitializeNextDecoder(const scoped_refptr<DemuxerStream>& demuxer_stream,
                              scoped_ptr<VideoDecoderList> decoders);
 
   // Called when |decoder_| initialization completes.
   // |demuxer_stream| & |decoders| are used if initialization failed and
   // InitializeNextDecoder() needs to be called again.
   void OnDecoderInitDone(const scoped_refptr<DemuxerStream>& demuxer_stream,
                          scoped_ptr<VideoDecoderList> decoders,
                          PipelineStatus status);
 
   scoped_refptr<base::MessageLoopProxy> message_loop_;
-  base::WeakPtrFactory<VideoRendererBase> weak_factory_;
-  base::WeakPtr<VideoRendererBase> weak_this_;
 
   // Used for accessing data members.
   base::Lock lock_;
 
   SetDecryptorReadyCB set_decryptor_ready_cb_;
 
   // These two will be set by VideoDecoderSelector::SelectVideoDecoder().
   scoped_refptr<VideoDecoder> decoder_;
   scoped_refptr<DecryptingDemuxerStream> decrypting_demuxer_stream_;
 
-  // Queue of incoming frames yet to be painted.
+  // Queue of incoming frames as well as the current frame since the last time
+  // OnFrameAvailable() was called.
   typedef std::deque<scoped_refptr<VideoFrame> > VideoFrameQueue;
   VideoFrameQueue ready_frames_;
 
+  // The current frame available to subclasses for rendering via
+  // GetCurrentFrame().  |current_frame_| can only be altered when
+  // |pending_paint_| is false.
+  scoped_refptr<VideoFrame> current_frame_;
+
+  // The previous |current_frame_| and is returned via GetCurrentFrame() in the
+  // situation where all frames were deallocated (i.e., during a flush).
+  //
+  // TODO(scherkus): remove this after getting rid of Get/PutCurrentFrame() in
+  // favour of passing ownership of the current frame to the renderer via
+  // callback.
+  scoped_refptr<VideoFrame> last_available_frame_;
+
   // Used to signal |thread_| as frames are added to |frames_|.  Rule of thumb:
   // always check |state_| to see if it was set to STOPPED after waking up!
   base::ConditionVariable frame_available_;
 
   // State transition Diagram of this class:
   //       [kUninitialized] -------> [kError]
   //              |
   //              | Initialize()
   //              V        All frames returned
   //   +------[kFlushed]<-----[kFlushing]<--- OnDecoderResetDone()
@@ skipping 26 matching lines @@
     kPlaying,
     kEnded,
     kStopped,
     kError,
   };
   State state_;
 
   // Video thread handle.
   base::PlatformThreadHandle thread_;
 
-  // Keep track of outstanding reads on the video decoder. Flushing can only
-  // complete once reads have completed.
+  // Keep track of various pending operations:
+  //   - |pending_read_| is true when there's an active video decoding request.
+  //   - |pending_paint_| is true when |current_frame_| is currently being
+  //     accessed by the subclass.
+  //   - |pending_paint_with_last_available_| is true when
+  //     |last_available_frame_| is currently being accessed by the subclass.
+  //
+  // Flushing cannot complete until both |pending_read_| and |pending_paint_|
+  // are false.
   bool pending_read_;
+  bool pending_paint_;
+  bool pending_paint_with_last_available_;
 
   bool drop_frames_;
 
   float playback_rate_;
 
   // Playback operation callbacks.
   base::Closure flush_cb_;
   PipelineStatusCB preroll_cb_;
 
   // Event callbacks.
   PipelineStatusCB init_cb_;
   StatisticsCB statistics_cb_;
   TimeCB max_time_cb_;
   NaturalSizeChangedCB size_changed_cb_;
   base::Closure ended_cb_;
   PipelineStatusCB error_cb_;
   TimeDeltaCB get_time_cb_;
   TimeDeltaCB get_duration_cb_;
 
   base::TimeDelta preroll_timestamp_;
 
   // Delayed frame used during kPrerolling to determine whether
   // |preroll_timestamp_| is between this frame and the next one.
   scoped_refptr<VideoFrame> prerolling_delayed_frame_;
 
   // Embedder callback for notifying a new frame is available for painting.
-  PaintCB paint_cb_;
+  base::Closure paint_cb_;
 
   // Callback to execute to inform the player if the video decoder's output is
   // opaque.
   SetOpaqueCB set_opaque_cb_;
 
   // The last natural size |size_changed_cb_| was called with.
-  //
-  // TODO(scherkus): WebMediaPlayerImpl should track this instead of plumbing
-  // this through Pipeline. The one tricky bit might be guaranteeing we deliver
-  // the size information before we reach HAVE_METADATA.
   gfx::Size last_natural_size_;
 
-  // The timestamp of the last frame removed from the |ready_frames_| queue,
-  // either for calling |paint_cb_| or for dropping. Set to kNoTimestamp()
-  // during flushing.
-  base::TimeDelta last_timestamp_;
-
   DISALLOW_COPY_AND_ASSIGN(VideoRendererBase);
 };
 
 }  // namespace media
 
 #endif  // MEDIA_FILTERS_VIDEO_RENDERER_BASE_H_