Add can-ignore-rect hint to clear call

include/gpu/GrContext.h

 /*
  * Copyright 2010 Google Inc.
  *
  * Use of this source code is governed by a BSD-style license that can be
  * found in the LICENSE file.
  */
 
 #ifndef GrContext_DEFINED
 #define GrContext_DEFINED
 
@@ skipping 361 matching lines @@
      */
     void setClip(const GrClipData* clipData) { fClip = clipData; }
 
     ///////////////////////////////////////////////////////////////////////////
     // Draws
 
     /**
      * Clear the entire or rect of the render target, ignoring any clips.
      * @param rect  the rect to clear or the whole thing if rect is NULL.
      * @param color the color to clear to.
+     * @param canIgnoreRect allows partial clears to be converted to whole
+     *                      clears on platforms for which that is cheap
      * @param target if non-NULL, the render target to clear otherwise clear
      *               the current render target
      */
-    void clear(const SkIRect* rect, GrColor color,
+    void clear(const SkIRect* rect, GrColor color, bool canIgnoreRect,
                GrRenderTarget* target = NULL);
 
     /**
      *  Draw everywhere (respecting the clip) with the paint.
      */
     void drawPaint(const GrPaint& paint);
 
     /**
      *  Draw the rect using a paint.
      *  @param paint        describes how to color pixels.
@@ skipping 632 matching lines @@
     }
 
     GrTexture* texture() { return fTexture; }
 
 private:
     GrContext*                    fContext;
     GrTexture*                    fTexture;
 };
 
 #endif