Implement MediaSession on top of the WebMediaPlayerDelegate.

content/content_common.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',
     '../components/tracing.gyp:tracing',
     '../gpu/command_buffer/command_buffer.gyp:gles2_utils',
     '../net/net.gyp:net',
@@ skipping 420 matching lines @@
       'common/mac/font_descriptor.mm',
       'common/mac/font_loader.h',
       'common/mac/font_loader.mm',
       'common/manifest_manager_messages.h',
       'common/media/aec_dump_messages.h',
       'common/media/audio_messages.h',
       'common/media/cdm_messages.h',
       'common/media/cdm_messages_enums.h',
       'common/media/media_param_traits.cc',
       'common/media/media_param_traits.h',
+      'common/media/media_player_delegate_messages.h',
       'common/media/media_player_messages_android.h',
       'common/media/media_session_messages_android.h',
       'common/media/media_stream_messages.h',
       'common/media/media_stream_options.cc',
       'common/media/media_stream_options.h',
       'common/media/media_stream_track_metrics_host_messages.h',
       'common/media/midi_messages.h',
       'common/media/video_capture.h',
       'common/media/video_capture_messages.h',
       'common/media/webrtc_identity_messages.h',
@@ skipping 668 matching lines @@
         'common/gpu/client/gpu_memory_buffer_impl_ozone.cc',
         'common/gpu/client/gpu_memory_buffer_impl_ozone_native_pixmap.cc',
         'common/gpu/client/gpu_memory_buffer_impl_ozone_native_pixmap.h',
         'common/gpu/gpu_memory_buffer_factory_ozone.cc',
         'common/gpu/gpu_memory_buffer_factory_ozone_native_pixmap.cc',
         'common/gpu/gpu_memory_buffer_factory_ozone_native_pixmap.h',
       ],
     }],
   ],
 }