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

Source/core/html/canvas/WebGLObject.h

Index: Source/core/html/canvas/WebGLObject.h
diff --git a/Source/core/html/canvas/WebGLObject.h b/Source/core/html/canvas/WebGLObject.h
index ae5c439c8a6be5f9d8a5ff3f930100daa3508a78..aaa9c4b76b34882375bc40012d8009d6404c5748 100644
--- a/Source/core/html/canvas/WebGLObject.h
+++ b/Source/core/html/canvas/WebGLObject.h
@@ -27,6 +27,7 @@
 #define WebGLObject_h
 
 #include "platform/graphics/GraphicsTypes3D.h"
+#include "platform/heap/Handle.h"
 #include "wtf/RefCounted.h"
 
 namespace blink {
@@ -38,7 +39,7 @@ namespace WebCore {
 class WebGLContextGroup;
 class WebGLRenderingContextBase;
 
-class WebGLObject : public RefCounted<WebGLObject> {
+class WebGLObject : public RefCountedWillBeGarbageCollectedFinalized<WebGLObject> {
 public:
     virtual ~WebGLObject();
 
@@ -60,6 +61,8 @@ public:
     // True if this object belongs to the group or context.
     virtual bool validate(const WebGLContextGroup*, const WebGLRenderingContextBase*) const = 0;
 
+    virtual void trace(Visitor*) { }
+
 protected:
     WebGLObject(WebGLRenderingContextBase*);