Extract common simulcast logic from VP8 wrapper and simulcast adapter

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("../../build/webrtc.gni")
 
@@ skipping 94 matching lines @@
   sources = [
     "utility/frame_dropper.cc",
     "utility/frame_dropper.h",
     "utility/ivf_file_writer.cc",
     "utility/ivf_file_writer.h",
     "utility/moving_average.h",
     "utility/qp_parser.cc",
     "utility/qp_parser.h",
     "utility/quality_scaler.cc",
     "utility/quality_scaler.h",
+    "utility/simulcast_state.cc",
+    "utility/simulcast_state.h",
     "utility/vp8_header_parser.cc",
     "utility/vp8_header_parser.h",
   ]
 
   configs += [ "../..:common_config" ]
   public_configs = [ "../..:common_inherited_config" ]
 
   if (is_clang) {
     # Suppress warnings from Chrome's Clang plugins.
     # See http://code.google.com/p/webrtc/issues/detail?id=163 for details.
@@ skipping 134 matching lines @@
 
   deps = [
     ":video_coding_utility",
     "../../common_video",
     "../../system_wrappers",
   ]
   if (rtc_build_libvpx) {
     deps += [ rtc_libvpx_dir ]
   }
 }