Make MediaSession a runtime-enabled feature on Desktop.

content/content_tests.gypi

 # Copyright (c) 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': {
     'layouttest_support_content_sources': [
       'public/test/layouttest_support.h',
       'public/test/nested_message_pump_android.cc',
       'public/test/nested_message_pump_android.h',
@@ skipping 214 matching lines @@
       'browser/gpu/gpu_ipc_browsertests.cc',
       'browser/host_zoom_map_impl_browsertest.cc',
       'browser/indexed_db/indexed_db_browsertest.cc',
       'browser/indexed_db/mock_browsertest_indexed_db_class_factory.cc',
       'browser/indexed_db/mock_browsertest_indexed_db_class_factory.h',
       'browser/loader/async_resource_handler_browsertest.cc',
       'browser/loader/async_revalidation_manager_browsertest.cc',
       'browser/loader/cross_site_resource_handler_browsertest.cc',
       'browser/loader/resource_dispatcher_host_browsertest.cc',
       'browser/manifest/manifest_browsertest.cc',
-      'browser/media/android/media_session_browsertest.cc',
       'browser/media/encrypted_media_browsertest.cc',
       'browser/media/media_browsertest.cc',
       'browser/media/media_browsertest.h',
       'browser/media/media_canplaytype_browsertest.cc',
       'browser/media/media_source_browsertest.cc',
+      'browser/media/session/media_session_browsertest.cc',
       'browser/memory/memory_pressure_controller_impl_browsertest.cc',
       'browser/message_port_provider_browsertest.cc',
       'browser/mojo_shell_browsertest.cc',
       'browser/net_info_browsertest.cc',
       'browser/renderer_host/input/composited_scrolling_browsertest.cc',
       'browser/renderer_host/input/touch_action_browsertest.cc',
       'browser/renderer_host/input/touch_input_browsertest.cc',
       'browser/renderer_host/input/touch_selection_controller_client_aura_browsertest.cc',
       'browser/renderer_host/render_process_host_browsertest.cc',
       'browser/renderer_host/render_view_host_browsertest.cc',
@@ skipping 241 matching lines @@
       'browser/loader/async_revalidation_manager_unittest.cc',
       'browser/loader/mime_type_resource_handler_unittest.cc',
       'browser/loader/navigation_url_loader_unittest.cc',
       'browser/loader/resource_buffer_unittest.cc',
       'browser/loader/resource_dispatcher_host_unittest.cc',
       'browser/loader/resource_loader_unittest.cc',
       'browser/loader/resource_scheduler_unittest.cc',
       'browser/loader/temporary_file_stream_unittest.cc',
       'browser/loader/upload_data_stream_builder_unittest.cc',
       'browser/mach_broker_mac_unittest.cc',
-      'browser/media/android/media_session_uma_helper_unittest.cc',
-      'browser/media/android/media_session_controller_unittest.cc',
       'browser/media/audible_metrics_unittest.cc',
       'browser/media/audio_stream_monitor_unittest.cc',
       'browser/media/capture/audio_mirroring_manager_unittest.cc',
       'browser/media/capture/cursor_renderer_aura_unittest.cc',
       'browser/media/capture/web_contents_audio_input_stream_unittest.cc',
       'browser/media/capture/web_contents_video_capture_device_unittest.cc',
       'browser/media/media_internals_unittest.cc',
       'browser/media/midi_host_unittest.cc',
+      'browser/media/session/media_session_uma_helper_unittest.cc',
+      'browser/media/session/media_session_controller_unittest.cc',
       'browser/media/webrtc_identity_store_unittest.cc',
       'browser/net/quota_policy_cookie_store_unittest.cc',
       'browser/notification_service_impl_unittest.cc',
       'browser/notifications/notification_database_data_unittest.cc',
       'browser/notifications/notification_database_unittest.cc',
       'browser/notifications/notification_id_generator_unittest.cc',
       'browser/notifications/platform_notification_context_unittest.cc',
       'browser/power_monitor_message_broadcaster_unittest.cc',
       'browser/power_usage_monitor_impl_unittest.cc',
       'browser/presentation/presentation_service_impl_unittest.cc',
@@ skipping 1715 matching lines @@
                   'content_unittests_apk.isolate',
                 ],
               },
             ],
           },
         ],
       ],
     }],
   ],
 }