Fix/Add content_unittests to work for the code behind --enable-audio-track-processing

content/content_tests.gypi

 # Copyright (c) 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.
 
 {
   'targets': [
     {
       'target_name': 'test_support_content',
       'type': 'static_library',
       'dependencies': [
@@ skipping 696 matching lines @@
             'browser/renderer_host/media/webrtc_identity_service_host_unittest.cc',
             'browser/renderer_host/p2p/socket_host_test_utils.cc',
             'browser/renderer_host/p2p/socket_host_test_utils.h',
             'browser/renderer_host/p2p/socket_host_tcp_unittest.cc',
             'browser/renderer_host/p2p/socket_host_tcp_server_unittest.cc',
             'browser/renderer_host/p2p/socket_host_udp_unittest.cc',
             'renderer/media/media_stream_audio_processor_unittest.cc',
             'renderer/media/media_stream_dependency_factory_unittest.cc',
             'renderer/media/media_stream_dispatcher_unittest.cc',
             'renderer/media/media_stream_impl_unittest.cc',
+            'renderer/media/mock_media_constraint_factory.cc',
             'renderer/media/rtc_peer_connection_handler_unittest.cc',
             'renderer/media/rtc_video_decoder_unittest.cc',
             'renderer/media/video_source_handler_unittest.cc',
             'renderer/media/webrtc/webrtc_local_audio_track_adapter_unittest.cc',
             'renderer/media/webrtc/webrtc_video_capturer_adapter_unittest.cc',
             'renderer/media/webrtc_audio_capturer_unittest.cc',
             'renderer/media/webrtc_audio_device_unittest.cc',
             'renderer/media/webrtc_identity_service_unittest.cc',
             'renderer/media/webrtc_local_audio_source_provider_unittest.cc',
             'renderer/media/webrtc_local_audio_track_unittest.cc',
@@ skipping 993 matching lines @@
                   'files': ['<(PRODUCT_DIR)/libnpapi_test_plugin.so'],
                 },
               ],
             }],
           ],
         },
       ],
     }],
   ],
 }