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

webrtc/api/BUILD.gn

 # Copyright (c) 2015 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.
 
 import("../webrtc.gni")
 if (is_android) {
@@ skipping 150 matching lines @@
 rtc_source_set("transport_api") {
   sources = [
     "call/transport.h",
   ]
 }
 
 rtc_source_set("video_frame_api") {
   sources = [
     "video/i420_buffer.cc",
     "video/i420_buffer.h",
+    "video/video_content_type.cc",
+    "video/video_content_type.h",
     "video/video_frame.cc",
     "video/video_frame.h",
     "video/video_frame_buffer.cc",
     "video/video_frame_buffer.h",
     "video/video_rotation.h",
     "video/video_timing.cc",
     "video/video_timing.h",
   ]
 
   deps = [
@@ skipping 82 matching lines @@
       suppressed_configs += [ "//build/config/clang:find_bad_constructs" ]
     }
 
     deps = [
       ":libjingle_peerconnection_api",
       ":ortc_api",
       "../test:test_support",
     ]
   }
 }