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

webrtc/modules/video_coding/BUILD.gn

 # 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.
 
 import("../../webrtc.gni")
 
@@ skipping 86 matching lines @@
     "..:module_api",
     "../..:webrtc_common",
     "../../call:video_stream_api",
     "../../common_video",
     "../../rtc_base:rtc_base",
     "../../rtc_base:rtc_base_approved",
     "../../rtc_base:rtc_numerics",
     "../../rtc_base:rtc_task_queue",
     "../../rtc_base:sequenced_task_checker",
     "../../system_wrappers",
+    "../pacing",
     "../rtp_rtcp:rtp_rtcp",
     "../utility:utility",
   ]
 }
 
 rtc_static_library("video_coding_utility") {
   sources = [
     "utility/default_video_bitrate_allocator.cc",
     "utility/default_video_bitrate_allocator.h",
     "utility/frame_dropper.cc",
@@ skipping 520 matching lines @@
     }
 
     # TODO(jschuh): bugs.webrtc.org/1348: fix this warning.
     configs += [ "//build/config/compiler:no_size_t_to_int_warning" ]
     if (!build_with_chromium && is_clang) {
       # Suppress warnings from the Chromium Clang plugin (bugs.webrtc.org/163).
       suppressed_configs += [ "//build/config/clang:find_bad_constructs" ]
     }
   }
 }