Add QP for libvpx VP8 decoder.

webrtc/modules/video_coding/codecs/vp8/vp8_impl.h

 /*
  *  Copyright (c) 2012 The WebRTC project authors. All Rights Reserved.
  *
  *  Use of this source code is governed by a BSD-style license
  *  that can be found in the LICENSE file in the root of the source
  *  tree. An additional intellectual property rights grant can be found
  *  in the file PATENTS.  All contributing project authors may
  *  be found in the AUTHORS file in the root of the source tree.
  *
  * WEBRTC VP8 wrapper interface
@@ skipping 131 matching lines @@
   // Copy reference image from this _decoder to the _decoder in copyTo. Set
   // which frame type to copy in _refFrame->frame_type before the call to
   // this function.
   int CopyReference(VP8DecoderImpl* copy);
 
   int DecodePartitions(const EncodedImage& input_image,
                        const RTPFragmentationHeader* fragmentation);
 
   int ReturnFrame(const vpx_image_t* img,
                   uint32_t timeStamp,
-                  int64_t ntp_time_ms);
+                  int64_t ntp_time_ms,
+                  int qp);
 
   I420BufferPool buffer_pool_;
   DecodedImageCallback* decode_complete_callback_;
   bool inited_;
   bool feedback_mode_;
   vpx_codec_ctx_t* decoder_;
   VideoCodec codec_;
   int image_format_;
   vpx_ref_frame_t* ref_frame_;
   int propagation_cnt_;
   int last_frame_width_;
   int last_frame_height_;
   bool key_frame_required_;
 };  // end of VP8DecoderImpl class
 }  // namespace webrtc
 
 #endif  // WEBRTC_MODULES_VIDEO_CODING_CODECS_VP8_VP8_IMPL_H_