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

tests/WritePixelsTest.cpp

Index: tests/WritePixelsTest.cpp
diff --git a/tests/WritePixelsTest.cpp b/tests/WritePixelsTest.cpp
index 1839a4018338435cfc55c6d29e2a189ad71485c2..c59aa2d254ae56f65ba607a7e35329f7409cf5f2 100644
--- a/tests/WritePixelsTest.cpp
+++ b/tests/WritePixelsTest.cpp
@@ -8,7 +8,6 @@
 #include "SkCanvas.h"
 #include "SkColorPriv.h"
 #include "SkMathPriv.h"
-#include "SkRegion.h"
 #include "SkSurface.h"
 #include "Test.h"
 #include "sk_tool_utils.h"
@@ -121,7 +120,7 @@ static void fill_canvas(SkCanvas* canvas) {
     }
     canvas->save();
     canvas->setMatrix(SkMatrix::I());
-    canvas->clipRect(DEV_RECT_S, SkRegion::kReplace_Op);
+    canvas->clipRect(DEV_RECT_S, SkCanvas::kReplace_Op);
     SkPaint paint;
     paint.setXfermodeMode(SkXfermode::kSrc_Mode);
     canvas->drawBitmap(bmp, 0, 0, &paint);