Simple GPU based dithering

src/gpu/effects/GrDitherEffect.h

 /*
  * Copyright 2014 Google Inc.
  *
  * Use of this source code is governed by a BSD-style license that can be
  * found in the LICENSE file.
  */
 
-#ifndef GrOvalEffect_DEFINED
-#define GrOvalEffect_DEFINED
+#ifndef GrDitherEffect_DEFINED
+#define GrDitherEffect_DEFINED
 
 #include "GrTypes.h"
 #include "GrTypesPriv.h"
 
 class GrEffectRef;
-struct SkRect;
 
-namespace GrOvalEffect {
+namespace GrDitherEffect {
     /**
-     * Creates an effect that performs clipping against an oval.
+     * Creates an effect that dithers the resulting color to an RGBA8 framebuffer
      */
-    GrEffectRef* Create(GrEffectEdgeType, const SkRect&);
+    GrEffectRef* Create();
 };
 
 #endif