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

src/effects/SkXfermodeImageFilter.cpp

 /*
  * Copyright 2013 The Android Open Source Project
  *
  * Use of this source code is governed by a BSD-style license that can be
  * found in the LICENSE file.
  */
 
 #include "SkXfermodeImageFilter.h"
 
 #include "SkCanvas.h"
@@ skipping 107 matching lines @@
     }
 
     paint.setXfermode(fMode);
 
     if (foreground) {
         foreground->draw(canvas,
                          SkIntToScalar(foregroundOffset.fX), SkIntToScalar(foregroundOffset.fY),
                          &paint);
     }
 
-    canvas->clipRect(SkRect::Make(foregroundBounds), SkRegion::kDifference_Op);
+    canvas->clipRect(SkRect::Make(foregroundBounds), SkCanvas::kDifference_Op);
     paint.setColor(SK_ColorTRANSPARENT);
     canvas->drawPaint(paint);
 
     return surf->makeImageSnapshot();
 }
 
 #ifndef SK_IGNORE_TO_STRING
 void SkXfermodeImageFilter::toString(SkString* str) const {
     str->appendf("SkXfermodeImageFilter: (");
     str->appendf("xfermode: (");
@@ skipping 114 matching lines @@
     matrix.setTranslate(SkIntToScalar(-bounds.left()), SkIntToScalar(-bounds.top()));
     drawContext->drawRect(GrNoClip(), paint, matrix, SkRect::Make(bounds));
 
     return SkSpecialImage::MakeFromGpu(SkIRect::MakeWH(bounds.width(), bounds.height()),
                                        kNeedNewImageUniqueID_SpecialImage,
                                        drawContext->asTexture(),
                                        sk_ref_sp(drawContext->getColorSpace()));
 }
 
 #endif