Oilpan: make DOMWindowProperty a GC mixin.

Source/modules/webmidi/NavigatorWebMIDI.cpp

 /*
  * Copyright (C) 2013 Google Inc. All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions are
  * met:
  *
  *     * Redistributions of source code must retain the above copyright
  * notice, this list of conditions and the following disclaimer.
  *     * Redistributions in binary form must reproduce the above
@@ skipping 29 matching lines @@
 #include "modules/webmidi/MIDIAccessInitializer.h"
 #include "modules/webmidi/MIDIOptions.h"
 
 namespace blink {
 
 NavigatorWebMIDI::NavigatorWebMIDI(LocalFrame* frame)
     : DOMWindowProperty(frame)
 {
 }
 
-NavigatorWebMIDI::~NavigatorWebMIDI()
+DEFINE_EMPTY_DESTRUCTOR_WILL_BE_REMOVED(NavigatorWebMIDI);
+
+void NavigatorWebMIDI::trace(Visitor* visitor)
 {
+    WillBeHeapSupplement<Navigator>::trace(visitor);
+    DOMWindowProperty::trace(visitor);
 }
 
 const char* NavigatorWebMIDI::supplementName()
 {
     return "NavigatorWebMIDI";
 }
 
 NavigatorWebMIDI& NavigatorWebMIDI::from(Navigator& navigator)
 {
     NavigatorWebMIDI* supplement = static_cast<NavigatorWebMIDI*>(WillBeHeapSupplement<Navigator>::from(navigator, supplementName()));
@@ skipping 16 matching lines @@
         ScriptPromise promise = resolver->promise();
         // FIXME: Currently this rejection does not work because the context is stopped.
         resolver->reject(DOMError::create("AbortError"));
         return promise;
     }
 
     return MIDIAccessInitializer::start(scriptState, MIDIOptions(options));
 }
 
 } // namespace blink