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

webrtc/modules/video_coding/generic_decoder.cc

 /*
  *  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 171 matching lines @@
   return VCM_OK;
 }
 
 VCMGenericDecoder::VCMGenericDecoder(VideoDecoder* decoder, bool isExternal)
     : _callback(NULL),
       _frameInfos(),
       _nextFrameInfoIdx(0),
       decoder_(decoder),
       _codecType(kVideoCodecUnknown),
       _isExternal(isExternal),
-      _last_keyframe_content_type(VideoContentType::UNSPECIFIED) {
+      _last_keyframe_content_type(VideoContentType::Unspecified()) {
   RTC_DCHECK(decoder_);
 }
 
 VCMGenericDecoder::~VCMGenericDecoder() {
   decoder_->Release();
   if (_isExternal)
     decoder_.release();
   RTC_DCHECK(_isExternal || decoder_);
 }
 
@@ skipping 47 matching lines @@
     VCMDecodedFrameCallback* callback) {
   _callback = callback;
   return decoder_->RegisterDecodeCompleteCallback(callback);
 }
 
 bool VCMGenericDecoder::PrefersLateDecoding() const {
   return decoder_->PrefersLateDecoding();
 }
 
 }  // namespace webrtc