Add metrics to track the duration of tracks received over a PeerConnection.

content/content_browser.gypi

 # Copyright (c) 2012 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.
 
 {
   'dependencies': [
     '../third_party/re2/re2.gyp:re2',
     '../base/base.gyp:base_static',
     '../crypto/crypto.gyp:crypto',
     '../google_apis/google_apis.gyp:google_apis',
@@ skipping 957 matching lines @@
     'browser/renderer_host/media/device_request_message_filter.cc',
     'browser/renderer_host/media/device_request_message_filter.h',
     'browser/renderer_host/media/media_stream_dispatcher_host.cc',
     'browser/renderer_host/media/media_stream_dispatcher_host.h',
     'browser/renderer_host/media/media_stream_manager.cc',
     'browser/renderer_host/media/media_stream_manager.h',
     'browser/renderer_host/media/media_stream_provider.h',
     'browser/renderer_host/media/media_stream_requester.h',
     'browser/renderer_host/media/media_stream_ui_proxy.cc',
     'browser/renderer_host/media/media_stream_ui_proxy.h',
+    'browser/renderer_host/media/media_track_lifetime_metrics_host.cc',

[perkj_chrome, 2014/03/11 08:05:21]

humm- I think we call this media_stream_track etc in the renderer. 
How about media_stream_track_metrics_host.cc?

[Jói, 2014/03/11 17:36:33]

Done.

+    'browser/renderer_host/media/media_track_lifetime_metrics_host.h',
     'browser/renderer_host/media/midi_dispatcher_host.cc',
     'browser/renderer_host/media/midi_dispatcher_host.h',
     'browser/renderer_host/media/midi_host.cc',
     'browser/renderer_host/media/midi_host.h',
     'browser/renderer_host/media/video_capture_buffer_pool.cc',
     'browser/renderer_host/media/video_capture_buffer_pool.h',
     'browser/renderer_host/media/video_capture_controller.cc',
     'browser/renderer_host/media/video_capture_controller.h',
     'browser/renderer_host/media/video_capture_controller_event_handler.cc',
     'browser/renderer_host/media/video_capture_controller_event_handler.h',
@@ skipping 692 matching lines @@
         '../build/linux/system.gyp:dbus',
         '../dbus/dbus.gyp:dbus',
       ],
     }, {  # OS != "linux" or use_dbus==0
       'sources!': [
         'browser/geolocation/wifi_data_provider_linux.cc',
       ],
     }],
   ],
 }