Oilpan: Remove guardRef and guardDeref from TreeScope.

Source/core/html/canvas/CanvasRenderingContext2D.idl

 /*
  * Copyright (C) 2006 Apple Computer, 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:
  * 1. Redistributions of source code must retain the above copyright
  *    notice, this list of conditions and the following disclaimer.
  * 2. 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 APPLE COMPUTER, INC. ``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 APPLE COMPUTER, INC. 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.
  */
 
 enum CanvasWindingRule { "nonzero", "evenodd" };
 
-interface CanvasRenderingContext2D {
+[
+    WillBeGarbageCollected
+] interface CanvasRenderingContext2D {
 
     readonly attribute HTMLCanvasElement canvas;
 
     void save();
     void restore();
 
     [StrictTypeChecking, RuntimeEnabled=ExperimentalCanvasFeatures] attribute SVGMatrix currentTransform;
     void scale(float sx, float sy);
     void rotate(float angle);
     void translate(float tx, float ty);
@@ skipping 124 matching lines @@
     [StrictTypeChecking, MeasureAs=CanvasRenderingContext2DDrawImageFromRect] void drawImageFromRect(
         HTMLImageElement? image, optional float sx, optional float sy, optional float sw, optional float sh,
         optional float dx, optional float dy, optional float dw, optional float dh, optional DOMString compositeOperation);
     [MeasureAs=CanvasRenderingContext2DSetShadow] void setShadow(float width, float height, float blur, [StrictTypeChecking] optional DOMString color, optional float alpha);
     [MeasureAs=CanvasRenderingContext2DSetShadow] void setShadow(float width, float height, float blur, float grayLevel, optional float alpha);
     [MeasureAs=CanvasRenderingContext2DSetShadow] void setShadow(float width, float height, float blur, float r, float g, float b, float a);
     [MeasureAs=CanvasRenderingContext2DSetShadow] void setShadow(float width, float height, float blur, float c, float m, float y, float k, float a);
 };
 
 CanvasRenderingContext2D implements CanvasPathMethods;