Implement setSinkId() for media elements without src.

third_party/WebKit/Source/modules/modules.gypi

 {
   'includes': [
     '../core/core_generated.gypi',
     'modules_generated.gypi',
   ],
   'variables': {
     # Experimental hooks for embedder to provide extra IDL and source files.
     #
     # Note: this is not a supported API. If you rely on this, you will be broken
     # from time to time as the code generator changes in backward incompatible
@@ skipping 739 matching lines @@
       'app_banner/AppBannerController.cpp',
       'app_banner/AppBannerController.h',
       'app_banner/AppBannerPromptResult.cpp',
       'app_banner/AppBannerPromptResult.h',
       'app_banner/BeforeInstallPromptEvent.cpp',
       'app_banner/BeforeInstallPromptEvent.h',
       'audio_output_devices/HTMLMediaElementAudioOutputDevice.cpp',
       'audio_output_devices/HTMLMediaElementAudioOutputDevice.h',
       'audio_output_devices/SetSinkIdCallbacks.cpp',
       'audio_output_devices/SetSinkIdCallbacks.h',
+      'audio_output_devices/AudioOutputDeviceClient.cpp',
+      'audio_output_devices/AudioOutputDeviceClient.h',
       'background_sync/PeriodicSyncEvent.cpp',
       'background_sync/PeriodicSyncEvent.h',
       'background_sync/PeriodicSyncManager.cpp',
       'background_sync/PeriodicSyncManager.h',
       'background_sync/PeriodicSyncRegistration.cpp',
       'background_sync/PeriodicSyncRegistration.h',
       'background_sync/ServiceWorkerGlobalScopeSync.h',
       'background_sync/ServiceWorkerRegistrationSync.cpp',
       'background_sync/ServiceWorkerRegistrationSync.h',
       'background_sync/SyncCallbacks.cpp',
@@ skipping 1105 matching lines @@
       'webaudio/AudioBasicProcessorHandlerTest.cpp',
       'webaudio/ConvolverNodeTest.cpp',
       'webaudio/DynamicsCompressorNodeTest.cpp',
       'webaudio/ScriptProcessorNodeTest.cpp',
       'webaudio/StereoPannerNodeTest.cpp',
       'websockets/DOMWebSocketTest.cpp',
       'websockets/DocumentWebSocketChannelTest.cpp',
     ],
   },
 }