Migrate vr to use inlined tracing

Source/modules/vr/VRPositionState.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 VRPositionState_h
 #define VRPositionState_h
 
 #include "bindings/core/v8/ScriptWrappable.h"
 #include "core/dom/DOMPoint.h"
 #include "platform/heap/Handle.h"
@@ skipping 14 matching lines @@
     double timeStamp() const { return m_timeStamp; }
     DOMPoint* orientation() const { return m_orientation; }
     DOMPoint* position() const { return m_position; }
     DOMPoint* angularVelocity() const { return m_angularVelocity; }
     DOMPoint* linearVelocity() const { return m_linearVelocity; }
     DOMPoint* angularAcceleration() const { return m_angularAcceleration; }
     DOMPoint* linearAcceleration() const { return m_linearAcceleration; }
 
     void setState(const blink::WebHMDSensorState&);
 
-    virtual void trace(Visitor*);
+    DECLARE_VIRTUAL_TRACE();
 
 private:
     VRPositionState();
 
     double m_timeStamp;
     Member<DOMPoint> m_orientation;
     Member<DOMPoint> m_position;
     Member<DOMPoint> m_angularVelocity;
     Member<DOMPoint> m_linearVelocity;
     Member<DOMPoint> m_angularAcceleration;
     Member<DOMPoint> m_linearAcceleration;
 };
 
 } // namespace blink
 
 #endif // VRPositionState_h