Replace VideoDecoder::media_format() with significantly simpler width()/height() methods.

media/base/filters.h

 // Copyright (c) 2011 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.
 
 // Filters are connected in a strongly typed manner, with downstream filters
 // always reading data from upstream filters.  Upstream filters have no clue
 // who is actually reading from them, and return the results via callbacks.
 //
 //                         DemuxerStream(Video) <- VideoDecoder <- VideoRenderer
 // DataSource <- Demuxer <
@@ skipping 207 matching lines @@
   //
   // A NULL frame represents a decoding error.
   typedef base::Callback<void(scoped_refptr<VideoFrame>)> ConsumeVideoFrameCB;
   void set_consume_video_frame_callback(const ConsumeVideoFrameCB& callback) {
     consume_video_frame_callback_ = callback;
   }
 
   // Indicate whether decoder provides its own output buffers
   virtual bool ProvidesBuffer() = 0;
 
-  // Returns the media format produced by this decoder.
-  virtual const MediaFormat& media_format() = 0;
+  // Returns the width and height of decoded video in pixels.
+  //
+  // Clients should NOT rely on these values to remain constant. Instead, use
+  // the width/height from decoded video frames themselves.
+  //
+  // TODO(scherkus): why not rely on prerolling and decoding a single frame to
+  // get dimensions?
+  virtual int width() = 0;
+  virtual int height() = 0;
 
  protected:
   // Executes the permanent callback to pass off decoded video.
   //
   // TODO(scherkus): name this ConsumeVideoFrame() once we fix the TODO in
   // VideoDecodeEngine::EventHandler to remove ConsumeVideoFrame() from there.
   void VideoFrameReady(scoped_refptr<VideoFrame> frame) {
     consume_video_frame_callback_.Run(frame);
   }
 
@@ skipping 63 matching lines @@
   // buffer.
   virtual bool HasEnded() = 0;
 
   // Sets the output volume.
   virtual void SetVolume(float volume) = 0;
 };
 
 }  // namespace media
 
 #endif  // MEDIA_BASE_FILTERS_H_