Fix black video frames when seeking (which also fixes flashing poster issue).

media/filters/video_renderer_base.h

 // Copyright (c) 2010 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.
 
 // 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, calling OnFrameAvailable() on subclasses to notify
 // when a frame is ready to display.
 //
 // The media filter methods Initialize(), Stop(), SetPlaybackRate() and Seek()
@@ skipping 126 matching lines @@
   int height_;
   VideoFrame::Format surface_format_;
   VideoFrame::SurfaceType surface_type_;
 
   // 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 frames_queue_ready_;
   VideoFrameQueue frames_queue_done_;
   scoped_refptr<VideoFrame> current_frame_;
+  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!
   ConditionVariable frame_available_;
 
   // State transition Diagram of this class:
   //       [kUninitialized] -------> [kError]
   //              |
   //              | Initialize()
   //              V        All frames returned
@@ skipping 36 matching lines @@
   // Previous time returned from the pipeline.
   base::TimeDelta previous_time_;
 
   // Keeps track of our pending buffers. We *must* have no pending reads
   // before executing the flush callback; We decrement it each time we receive
   // a buffer and increment it each time we send a buffer out. therefore if
   // decoder provides buffer, |pending_reads_| is always non-positive and if
   // renderer provides buffer, |pending_reads_| is always non-negative.
   int pending_reads_;
   bool pending_paint_;
+  bool pending_paint_with_last_available_;
 
   float playback_rate_;
 
   // Filter callbacks.
   scoped_ptr<FilterCallback> flush_callback_;
   scoped_ptr<FilterCallback> seek_callback_;
 
   base::TimeDelta seek_timestamp_;
 
   DISALLOW_COPY_AND_ASSIGN(VideoRendererBase);
 };
 
 }  // namespace media
 
 #endif  // MEDIA_FILTERS_VIDEO_RENDERER_BASE_H_