Adding WebRTC Auto Gain Control Test (linux)

chrome/chrome_tests.gypi

 # Copyright 2013 The Chromium Authors. All rights reserved.
 # Use of this source code is governed by a BSD-style license that can be
 # found in the LICENSE file.
 {
   'variables': {
     'chrome_browser_extensions_test_support_sources': [
       # A list of sources which is shared between different browser tests.
       'browser/apps/app_browsertest_util.cc',
       'browser/apps/app_browsertest_util.h',
       'browser/extensions/browsertest_util.cc',
@@ skipping 445 matching lines @@
       'browser/media/chrome_webrtc_getmediadevices_browsertest.cc',
       'browser/media/chrome_webrtc_perf_browsertest.cc',
       'browser/media/chrome_webrtc_typing_detection_browsertest.cc',
       'browser/media/chrome_webrtc_video_quality_browsertest.cc',
       'browser/media/chrome_webrtc_webcam_browsertest.cc',
       'browser/media/encrypted_media_istypesupported_browsertest.cc',
       'browser/media/media_stream_devices_controller_browsertest.cc',
       'browser/media/test_license_server.cc',
       'browser/media/test_license_server.h',
       'browser/media/test_license_server_config.h',
+      'browser/media/webrtc_browsertest_audio.h',
+      'browser/media/webrtc_browsertest_audio.cc',
       'browser/media/webrtc_browsertest_base.cc',
       'browser/media/webrtc_browsertest_base.h',
       'browser/media/webrtc_browsertest_common.cc',
       'browser/media/webrtc_browsertest_common.h',
       'browser/media/webrtc_browsertest_perf.cc',
       'browser/media/webrtc_browsertest_perf.h',
       'browser/media/wv_test_license_server_config.cc',
       'browser/media/wv_test_license_server_config.h',
       'browser/media_galleries/fileapi/iapps_finder_impl_win_browsertest.cc',
       'browser/media_galleries/fileapi/media_file_validator_browsertest.cc',
@@ skipping 2745 matching lines @@
             ['enable_webrtc==1', {
               'dependencies': [
                 '../third_party/libjingle/libjingle.gyp:libjingle_webrtc'
               ]
             }],
           ],
         }]
     }],
   ],  # 'conditions'
 }