Add missing traces for Supplement<> classes

third_party/WebKit/Source/modules/audio_output_devices/AudioOutputDeviceClient.cpp

 // Copyright 2015 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.
 
 #include "modules/audio_output_devices/AudioOutputDeviceClient.h"
 
 #include "core/dom/Document.h"
 #include "core/dom/ExecutionContext.h"
 #include "core/frame/LocalFrame.h"
 
@@ skipping 14 matching lines @@
         return nullptr;
 
     return static_cast<AudioOutputDeviceClient*>(Supplement<LocalFrame>::from(document->frame(), supplementName()));
 }
 
 void provideAudioOutputDeviceClientTo(LocalFrame& frame, AudioOutputDeviceClient* client)
 {
     frame.provideSupplement(AudioOutputDeviceClient::supplementName(), client);
 }
 
+DEFINE_TRACE(AudioOutputDeviceClient)
+{
+    Supplement<LocalFrame>::trace(visitor);
+}
+
 } // namespace blink