Add missing traces for Supplement<> classes

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

 // 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.
 
 #ifndef AudioOutputDeviceClient_h
 #define AudioOutputDeviceClient_h
 
+#include "core/frame/LocalFrame.h"
 #include "modules/ModulesExport.h"
 #include "platform/Supplementable.h"
 #include "public/platform/WebSetSinkIdCallbacks.h"
 #include <memory>
 
 namespace blink {
 
 class ExecutionContext;
-class LocalFrame;
 class WebString;
 class ScriptState;
 
-class AudioOutputDeviceClient : public Supplement<LocalFrame> {
+class MODULES_EXPORT AudioOutputDeviceClient : public Supplement<LocalFrame> {
 public:
     virtual ~AudioOutputDeviceClient() {}
 
     // Checks that a given sink exists and has permissions to be used from the origin of the current frame.
     virtual void checkIfAudioSinkExistsAndIsAuthorized(ExecutionContext*, const WebString& sinkId, std::unique_ptr<WebSetSinkIdCallbacks>) = 0;
 
+    DECLARE_VIRTUAL_TRACE();
+
     // Supplement requirements.
     static AudioOutputDeviceClient* from(ExecutionContext*);
     static const char* supplementName();
 };
 
 MODULES_EXPORT void provideAudioOutputDeviceClientTo(LocalFrame&, AudioOutputDeviceClient*);
 
 } // namespace blink
 
 #endif // AudioOutputDeviceClient_h