Oilpan: move 2D Canvas and WebGL objects to the heap.

Source/core/html/canvas/CanvasContextAttributes.h

 /*
  * Copyright (c) 2010, 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
  * copyright notice, this list of conditions and the following disclaimer
  * in the documentation and/or other materials provided with the
  * distribution.
  *
  * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
  * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
  * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
  * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
  * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
  * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
  * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
  * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
  * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
  * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  */
 
 #ifndef CanvasContextAttributes_h
 #define CanvasContextAttributes_h
 
+#include "platform/heap/Handle.h"
 #include "wtf/RefCounted.h"
 
 namespace blink {
 
 // A base class for any attributes that are needed which would affect
 // the creation of the Canvas's rendering context.
 
-class CanvasContextAttributes : public RefCounted<CanvasContextAttributes> {
-  public:
-    virtual ~CanvasContextAttributes();
+class CanvasContextAttributes : public RefCountedWillBeGarbageCollectedFinalized<CanvasContextAttributes> {
+    DECLARE_EMPTY_VIRTUAL_DESTRUCTOR_WILL_BE_REMOVED(CanvasContextAttributes);
+public:
+    virtual void trace(Visitor*) { }
 
-  protected:
+protected:
     CanvasContextAttributes();
 };
 
 } // namespace blink
 
 #endif // CanvasContextAttributes_h