use ClipOp instead of SkRegion for clipping

src/utils/SkPictureUtils.cpp

 /*
  * Copyright 2012 Google Inc.
  *
  * Use of this source code is governed by a BSD-style license that can be
  * found in the LICENSE file.
  */
 
 #include "SkBBoxHierarchy.h"
 #include "SkBitmapDevice.h"
 #include "SkCanvas.h"
@@ skipping 185 matching lines @@
     }
 
     SkTDArray<SkPixelRef*> array;
     PixelRefSet prset(&array);
 
     GatherPixelRefDevice device(SkScalarCeilToInt(pict->cullRect().width()), 
                                 SkScalarCeilToInt(pict->cullRect().height()), 
                                 &prset);
     SkNoSaveLayerCanvas canvas(&device);
 
-    canvas.clipRect(area, SkRegion::kIntersect_Op, false);
+    canvas.clipRect(area);
     canvas.drawPicture(pict);
 
     SkData* data = NULL;
     int count = array.count();
     if (count > 0) {
         data = SkData::NewFromMalloc(array.detach(), count * sizeof(SkPixelRef*));
     }
     return data;
 }
 
@@ skipping 11 matching lines @@
     if (pict->fBBH.get()) {
         byteCount += pict->fBBH->bytesUsed();
     }
     MeasureRecords visitor;
     for (unsigned curOp = 0; curOp < pict->fRecord->count(); curOp++) {
         byteCount += pict->fRecord->visit<size_t>(curOp, visitor);
     }
 
     return byteCount;
 }