Migrate vr to use inlined tracing

Source/modules/vr/VRDevice.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 VRDevice_h
 #define VRDevice_h
 
 #include "bindings/core/v8/ScriptWrappable.h"
 #include "modules/vr/VRHardwareUnit.h"
 #include "platform/heap/Handle.h"
 #include "wtf/Forward.h"
 #include "wtf/text/WTFString.h"
 
 namespace blink {
 
 class VRDevice : public GarbageCollectedFinalized<VRDevice>, public ScriptWrappable {
     DEFINE_WRAPPERTYPEINFO();
 public:
     unsigned index() const { return m_hardwareUnit->index(); }
     const String& hardwareUnitId() const { return m_hardwareUnit->hardwareUnitId(); }
     const String& deviceId() const { return m_deviceId; }
     const String& deviceName() const { return m_deviceName; }
 
     VRHardwareUnit* hardwareUnit() { return m_hardwareUnit; }
     const VRHardwareUnit* hardwareUnit() const { return m_hardwareUnit; }
 
     virtual void updateFromWebVRDevice(const WebVRDevice&);
 
-    virtual void trace(Visitor*);
+    DECLARE_VIRTUAL_TRACE();
 
 protected:
     explicit VRDevice(VRHardwareUnit*);
 
 private:
     Member<VRHardwareUnit> m_hardwareUnit;
     String m_deviceId;
     String m_deviceName;
 };
 
 using VRDeviceVector = HeapVector<Member<VRDevice>>;
 
 } // namespace blink
 
 #endif // VRDevice_h