Enable H.264 video WebRTC behind run-time flag and add WebRtcBrowserTest for H.264

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 2118 matching lines @@
         'chrome_resources.gyp:packed_extra_resources',
         'chrome_resources.gyp:packed_resources',
         'common/extensions/api/api.gyp:chrome_api',
         'renderer',
         'test_support_common',
         'test_support_sync_integration',
         'test_support_ui',
         '../base/base.gyp:base',
         '../base/base.gyp:base_i18n',
         '../base/base.gyp:test_support_base',
+        '../content/public/renderer/media/webrtc/finch_h264_with_openh264_ffmpeg.gyp:finch_h264_with_openh264_ffmpeg',
         '../components/components.gyp:autofill_content_risk_proto',
         '../components/components.gyp:autofill_content_test_support',
         '../components/components.gyp:captive_portal_test_support',
         '../components/components.gyp:certificate_reporting',
         '../components/components.gyp:dom_distiller_content_browser',
         '../components/components.gyp:dom_distiller_content_renderer',
         '../components/components.gyp:dom_distiller_test_support',
         '../components/components.gyp:guest_view_test_support',
         '../components/components.gyp:history_core_test_support',
         '../components/components.gyp:safe_browsing_db',
@@ skipping 1361 matching lines @@
             'browser',
           ],
           'sources': [
             'tools/service_discovery_sniffer/service_discovery_sniffer.cc',
             'tools/service_discovery_sniffer/service_discovery_sniffer.h',
           ],
         }]
     }],
   ],  # 'conditions'
 }