[Cast] Refactor/clean-up VideoReceiver to match AudioReceiver as closely as possible.

media/cast/video_sender/codecs/vp8/vp8_encoder.cc

 // Copyright 2013 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.
 //
 // TODO (pwestin): add a link to the design document describing the generic
 // protocol and the VP8 specific details.
 #include "media/cast/video_sender/codecs/vp8/vp8_encoder.h"
 
 #include <vector>
 
@@ skipping 159 matching lines @@
   } else {
     // Reference all acked frames (buffers).
     latest_frame_id_to_reference = GetLatestFrameIdToReference();
     GetCodecReferenceFlags(&flags);
     buffer_to_update = GetNextBufferToUpdate();
     GetCodecUpdateFlags(buffer_to_update, &flags);
   }
 
   // Note: The duration does not reflect the real time between frames. This is
   // done to keep the encoder happy.
+  //
+  // TODO(miu): This is a semi-hack.  We should consider using
+  // |video_frame->timestamp()| instead.
   uint32 duration = kVideoFrequency / cast_config_.max_frame_rate;
   if (vpx_codec_encode(encoder_.get(),
                        raw_image_,
                        timestamp_,
                        duration,
                        flags,
                        VPX_DL_REALTIME)) {
     return false;
   }
   timestamp_ += duration;
@@ skipping 206 matching lines @@
   float scale_parameter = 0.5;
   uint32 target_pct = optimal_buffer_size_ms * scale_parameter *
                       cast_config_.max_frame_rate / 10;
 
   // Don't go below 3 times the per frame bandwidth.
   return std::max(target_pct, kMinIntra);
 }
 
 }  // namespace cast
 }  // namespace media