Fix Gn Untracked headers in webrtc/modules/video_coding.

test/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")
 import("//build/config/ui.gni")
@@ skipping 553 matching lines @@
     "../call",
     "../call:rtp_sender",
     "../call:video_stream_api",
     "../common_video",
     "../logging:rtc_event_log_api",
     "../modules/audio_device:mock_audio_device",
     "../modules/audio_mixer:audio_mixer_impl",
     "../modules/audio_processing",
     "../modules/rtp_rtcp",
     "../modules/rtp_rtcp:mock_rtp_rtcp",
+    "../modules/video_coding:video_coding_utility",
     "../modules/video_coding:webrtc_h264",
     "../modules/video_coding:webrtc_vp8",
     "../modules/video_coding:webrtc_vp9",
     "../rtc_base:rtc_base_approved",
     "../rtc_base:rtc_task_queue",
     "../rtc_base:sequenced_task_checker",
     "../system_wrappers",
     "../video",
     "../voice_engine",
     "//testing/gmock",
@@ skipping 137 matching lines @@
     ]
     deps = [
       "../rtc_base:base_java",
       "//testing/android/native_test:native_test_java",
     ]
 
     # TODO(sakal): Fix build hooks crbug.com/webrtc/8148
     no_build_hooks = true
   }
 }