Use AudioStreamMonitor to control power save blocking.

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': [
     '../base/base.gyp:base_static',
     '../crypto/crypto.gyp:crypto',
     '../google_apis/google_apis.gyp:google_apis',
     '../net/net.gyp:net',
@@ skipping 812 matching lines @@
       'browser/mach_broker_mac.h',
       'browser/mach_broker_mac.mm',
       'browser/media/android/browser_demuxer_android.cc',
       'browser/media/android/browser_demuxer_android.h',
       'browser/media/android/browser_media_player_manager.cc',
       'browser/media/android/browser_media_player_manager.h',
       'browser/media/android/media_drm_credential_manager.cc',
       'browser/media/android/media_drm_credential_manager.h',
       'browser/media/android/media_resource_getter_impl.cc',
       'browser/media/android/media_resource_getter_impl.h',
+      'browser/media/audio_stream_monitor.cc',
+      'browser/media/audio_stream_monitor.h',
       'browser/media/capture/audio_mirroring_manager.cc',
       'browser/media/capture/audio_mirroring_manager.h',
       'browser/media/capture/content_video_capture_device_core.cc',
       'browser/media/capture/content_video_capture_device_core.h',
       'browser/media/capture/video_capture_oracle.cc',
       'browser/media/capture/video_capture_oracle.h',
       'browser/media/capture/web_contents_audio_input_stream.cc',
       'browser/media/capture/web_contents_audio_input_stream.h',
       'browser/media/capture/web_contents_capture_util.cc',
       'browser/media/capture/web_contents_capture_util.h',
@@ skipping 1027 matching lines @@
       'sources': [
         'browser/media/cdm/browser_cdm_manager.cc',
         'browser/media/cdm/browser_cdm_manager.h',
         # This works on Android because enable_browser_cdms==1 on Android.
         'browser/media/media_web_contents_observer.cc',
         'browser/media/media_web_contents_observer.h',
       ],
     }],
   ],
 }