Add histogram for end-to-end delay.

webrtc/modules/video_coding/codecs/vp9/vp9_impl.h

 /*
  *  Copyright (c) 2014 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.
  *
  */
@@ skipping 135 matching lines @@
              const CodecSpecificInfo* codec_specific_info,
              int64_t /*render_time_ms*/) override;
 
   int RegisterDecodeCompleteCallback(DecodedImageCallback* callback) override;
 
   int Release() override;
 
   const char* ImplementationName() const override;
 
  private:
-  int ReturnFrame(const vpx_image_t* img, uint32_t timeStamp);
+  int ReturnFrame(const vpx_image_t* img,
+                  uint32_t timestamp,
+                  int64_t ntp_time_ms);
 
   // Memory pool used to share buffers between libvpx and webrtc.
   Vp9FrameBufferPool frame_buffer_pool_;
   DecodedImageCallback* decode_complete_callback_;
   bool inited_;
   vpx_codec_ctx_t* decoder_;
   VideoCodec codec_;
   bool key_frame_required_;
 };
 }  // namespace webrtc
 
 #endif  // WEBRTC_MODULES_VIDEO_CODING_CODECS_VP9_VP9_IMPL_H_