Refactor media out of WebContentsImpl to MediaWebContentsObserver.

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',
     '../components/url_formatter/url_formatter.gyp:url_formatter',
     '../crypto/crypto.gyp:crypto',
     '../device/battery/battery.gyp:device_battery',
@@ skipping 992 matching lines @@
       'browser/media/capture/web_contents_video_capture_device.cc',
       'browser/media/capture/web_contents_video_capture_device.h',
       'browser/media/media_internals.cc',
       'browser/media/media_internals.h',
       'browser/media/media_internals_handler.cc',
       'browser/media/media_internals_handler.h',
       'browser/media/media_internals_proxy.cc',
       'browser/media/media_internals_proxy.h',
       'browser/media/media_internals_ui.cc',
       'browser/media/media_internals_ui.h',
+      'browser/media/media_web_contents_observer.cc',
+      'browser/media/media_web_contents_observer.h',
       'browser/media/midi_host.cc',
       'browser/media/midi_host.h',
       'browser/media/webrtc_identity_store.cc',
       'browser/media/webrtc_identity_store.h',
       'browser/media/webrtc_identity_store_backend.cc',
       'browser/media/webrtc_identity_store_backend.h',
       'browser/memory/memory_message_filter.cc',
       'browser/memory/memory_message_filter.h',
       'browser/memory/memory_pressure_controller.cc',
       'browser/memory/memory_pressure_controller.h',
@@ skipping 1141 matching lines @@
       ],
     }, {  # OS != "linux" or use_dbus==0
       'sources!': [
         'browser/geolocation/wifi_data_provider_linux.cc',
       ],
     }],
     ['enable_browser_cdms==1', {
       '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',
       ],
     }],
     ['OS == "linux"', {
       'dependencies': [
         '../third_party/boringssl/boringssl.gyp:boringssl',
       ],
     }],
     ['enable_webvr==1', {
       'sources': [
         'browser/vr/vr_device.cc',
         'browser/vr/vr_device.h',
         'browser/vr/vr_device_manager.cc',
         'browser/vr/vr_device_manager.h',
         'browser/vr/vr_device_provider.h',
       ]
     }],
     ['enable_webvr==1 and OS=="android"', {
       'sources': [
         'browser/vr/android/cardboard/cardboard_vr_device.cc',
         'browser/vr/android/cardboard/cardboard_vr_device.h',
         'browser/vr/android/cardboard/cardboard_vr_device_provider.cc',
         'browser/vr/android/cardboard/cardboard_vr_device_provider.h',
       ],
     }],
   ],
 }