Piggybacking simulcast id and ALR experiment id into video content type extension.

webrtc/modules/video_coding/include/video_coding_defines.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.
  */
 
@@ skipping 51 matching lines @@
   uint32_t numKeyFrames;
   uint32_t numDeltaFrames;
 };
 
 // Callback class used for passing decoded frames which are ready to be
 // rendered.
 class VCMReceiveCallback {
  public:
   virtual int32_t FrameToRender(VideoFrame& videoFrame,  // NOLINT
                                 rtc::Optional<uint8_t> qp,
-                                VideoContentType /*content_type*/) = 0;
+                                VideoContentType content_type) = 0;
 
   virtual int32_t ReceivedDecodedReferenceFrame(const uint64_t pictureId) {
     return -1;
   }
   // Called when the current receive codec changes.
   virtual void OnIncomingPayloadType(int payload_type) {}
   virtual void OnDecoderImplementationName(const char* implementation_name) {}
 
  protected:
   virtual ~VCMReceiveCallback() {}
 };
 
 // Callback class used for informing the user of the bit rate and frame rate,
 // and the name of the encoder.
 class VCMSendStatisticsCallback {
  public:
   virtual void SendStatistics(uint32_t bitRate, uint32_t frameRate) = 0;
 
  protected:
   virtual ~VCMSendStatisticsCallback() {}
 };
 
 // Callback class used for informing the user of the incoming bit rate and frame
 // rate.
 class VCMReceiveStatisticsCallback {
  public:
   virtual void OnReceiveRatesUpdated(uint32_t bitRate, uint32_t frameRate) = 0;
-  virtual void OnCompleteFrame(bool is_keyframe, size_t size_bytes) = 0;
+  virtual void OnCompleteFrame(bool is_keyframe,
+                               size_t size_bytes,
+                               VideoContentType content_type) = 0;
   virtual void OnDiscardedPacketsUpdated(int discarded_packets) = 0;
   virtual void OnFrameCountsUpdated(const FrameCounts& frame_counts) = 0;
   virtual void OnFrameBufferTimingsUpdated(int decode_ms,
                                            int max_decode_ms,
                                            int current_delay_ms,
                                            int target_delay_ms,
                                            int jitter_buffer_ms,
                                            int min_playout_delay_ms,
                                            int render_delay_ms) = 0;
 
@@ skipping 54 matching lines @@
  public:
   virtual void RequestKeyFrame() = 0;
 
  protected:
   virtual ~KeyFrameRequestSender() {}
 };
 
 }  // namespace webrtc
 
 #endif  // WEBRTC_MODULES_VIDEO_CODING_INCLUDE_VIDEO_CODING_DEFINES_H_