Add Media device notification to SystemMonitor and Mac impl

base/base.gyp

 # 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.
 
 {
   'variables': {
     'chromium_code': 1,
   },
   'includes': [
     '../build/win_precompile.gypi',
@@ skipping 203 matching lines @@
         'stringize_macros_unittest.cc',
         'stringprintf_unittest.cc',
         'synchronization/cancellation_flag_unittest.cc',
         'synchronization/condition_variable_unittest.cc',
         'synchronization/lock_unittest.cc',
         'synchronization/waitable_event_unittest.cc',
         'synchronization/waitable_event_watcher_unittest.cc',
         'sys_info_unittest.cc',
         'sys_string_conversions_mac_unittest.mm',
         'sys_string_conversions_unittest.cc',
+        'system_monitor/mock_devices_changed_observer.h',
         'system_monitor/system_monitor_unittest.cc',
         'template_util_unittest.cc',
         'test/trace_event_analyzer_unittest.cc',
         'threading/non_thread_safe_unittest.cc',
         'threading/platform_thread_unittest.cc',
         'threading/sequenced_worker_pool_unittest.cc',
         'threading/simple_thread_unittest.cc',
         'threading/thread_checker_unittest.cc',
         'threading/thread_collision_warner_unittest.cc',
         'threading/thread_local_storage_unittest.cc',
@@ skipping 232 matching lines @@
           'msvs_settings': {
             'VCLinkerTool': {
               'SubSystem': '2',         # Set /SUBSYSTEM:WINDOWS
             },
           },
         },
       ],
     }],
   ],
 }