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

Source/core/html/canvas/WebGLContextAttributes.h

Index: Source/core/html/canvas/WebGLContextAttributes.h
diff --git a/Source/core/html/canvas/WebGLContextAttributes.h b/Source/core/html/canvas/WebGLContextAttributes.h
index 2c00ceb5ef942f1dd9df57543ed9d85b630093b5..f013a550774227b360f21d32895295357fa50af9 100644
--- a/Source/core/html/canvas/WebGLContextAttributes.h
+++ b/Source/core/html/canvas/WebGLContextAttributes.h
@@ -41,10 +41,10 @@ public:
     virtual ~WebGLContextAttributes();
 
     // Create a new attributes object
-    static PassRefPtr<WebGLContextAttributes> create();
+    static PassRefPtrWillBeRawPtr<WebGLContextAttributes> create();
 
     // Create a copy of this object.
-    PassRefPtr<WebGLContextAttributes> clone() const;
+    PassRefPtrWillBeRawPtr<WebGLContextAttributes> clone() const;
 
     // Whether or not the drawing buffer has an alpha channel; default=true
     bool alpha() const;