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

samplecode/SampleClip.cpp

Index: samplecode/SampleClip.cpp
diff --git a/samplecode/SampleClip.cpp b/samplecode/SampleClip.cpp
index 16390d8fb4efec346525eb355c561a3b60409500..06bd717ece04215d6d71966a7450ddabb4e80a1f 100644
--- a/samplecode/SampleClip.cpp
+++ b/samplecode/SampleClip.cpp
@@ -143,7 +143,7 @@ protected:
             canvas->save();
             for (size_t i = 0; i < SK_ARRAY_COUNT(gProc); ++i) {
                 canvas->save();
-                canvas->clipPath(clipPath, SkRegion::kIntersect_Op, SkToBool(aa));
+                canvas->clipPath(clipPath, SkCanvas::kIntersect_Op, SkToBool(aa));
 //                canvas->drawColor(SK_ColorWHITE);
                 gProc[i](canvas, SkToBool(aa));
                 canvas->restore();