Specialize GrConvexPolyEffect for AA rects, use for AA clip rects.

src/gpu/effects/GrConvexPolyEffect.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 GrConvexPolyEffect_DEFINED
 #define GrConvexPolyEffect_DEFINED
 
@@ skipping 43 matching lines @@
         return CreateEffectRef(AutoEffectUnref(SkNEW_ARGS(GrConvexPolyEffect,
                                                           (edgeType, n, edges))));
     }
 
     /**
      * Creates an effect that clips against the path. If the path is not a convex polygon, is
      * inverse filled, or has too many edges, this will return NULL.
      */
     static GrEffectRef* Create(EdgeType, const SkPath&);
 
+    /**
+     * Creates an effect that clips against the rect.
+     */
+    static GrEffectRef* Create(EdgeType, const SkRect&);
+
     virtual ~GrConvexPolyEffect();
 
     static const char* Name() { return "ConvexPoly"; }
 
     EdgeType getEdgeType() const { return fEdgeType; }
 
     int getEdgeCount() const { return fEdgeCount; }
 
     const SkScalar* getEdges() const { return fEdges; }
 
@@ skipping 12 matching lines @@
     int      fEdgeCount;
     SkScalar fEdges[3 * kMaxEdges];
 
     GR_DECLARE_EFFECT_TEST;
 
     typedef GrEffect INHERITED;
 };
 
 
 #endif