Add desktop engagement metrics.

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': {
     'build_angle_deqp_tests%': 0,
     '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',
@@ skipping 349 matching lines @@
       'browser/media/webrtc_video_quality_browsertest.cc',
       'browser/media/webrtc_webcam_browsertest.cc',
       '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',
       'browser/media_galleries/media_galleries_dialog_controller_mock.cc',
       'browser/media_galleries/media_galleries_dialog_controller_mock.h',
       'browser/memory/tab_manager_browsertest.cc',
       'browser/memory/tab_manager_observer_browsertest.cc',
+      'browser/metrics/desktop_engagement/audible_contents_tracker_browsertest.cc',
+      'browser/metrics/desktop_engagement/chrome_visibility_observer_browsertest.cc',
       'browser/metrics/metrics_memory_details_browsertest.cc',
       'browser/metrics/metrics_service_browsertest.cc',
       'browser/net/cookie_policy_browsertest.cc',
       'browser/net/dns_probe_browsertest.cc',
       'browser/net/ftp_browsertest.cc',
       'browser/net/load_timing_browsertest.cc',
       'browser/net/nss_context_chromeos_browsertest.cc',
       'browser/net/predictor_browsertest.cc',
       'browser/net/proxy_browsertest.cc',
       'browser/net/sdch_browsertest.cc',
@@ skipping 3208 matching lines @@
             'browser',
           ],
           'sources': [
             'tools/service_discovery_sniffer/service_discovery_sniffer.cc',
             'tools/service_discovery_sniffer/service_discovery_sniffer.h',
           ],
         }]
     }],
   ],  # 'conditions'
 }