abstract name of clipping ops, to transtion to a more restricted set

gm/complexclip_blur_tiled.cpp

 /*
  * Copyright 2016 Google Inc.
  *
  * Use of this source code is governed by a BSD-style license that can be
  * found in the LICENSE file.
  */
 
 #include "gm.h"
 #include "SkBlurImageFilter.h"
 #include "SkRRect.h"
@@ skipping 34 matching lines @@
         }
         SkCanvas* tileCanvas = tileSurface->getCanvas();
         for (SkScalar y = bounds.top(); y < bounds.bottom(); y += tileSize) {
             for (SkScalar x = bounds.left(); x < bounds.right(); x += tileSize) {
                 tileCanvas->save();
                 tileCanvas->clear(0);
                 tileCanvas->translate(-x, -y);
                 SkRect rect = SkRect::MakeWH(WIDTH, HEIGHT);
                 tileCanvas->saveLayer(&rect, &blurPaint);
                 SkRRect rrect = SkRRect::MakeRectXY(rect.makeInset(20, 20), 25, 25);
-                tileCanvas->clipRRect(rrect, SkRegion::kDifference_Op, true);
+                tileCanvas->clipRRect(rrect, SkCanvas::kDifference_Op, true);
                 SkPaint paint;
                 tileCanvas->drawRect(rect, paint);
                 tileCanvas->restore();
                 tileCanvas->restore();
                 canvas->drawImage(tileSurface->makeImageSnapshot().get(), x, y);
             }
         }
     }
 
 private:
     typedef GM INHERITED;
 };
 
 //////////////////////////////////////////////////////////////////////////////
 
 DEF_GM(return new ComplexClipBlurTiledGM;)
 
 }