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

SkRegion::Op --> SkCanvas::ClipOp (alias) --> SkClipOp

pre-CL needed in chrome : https://codereview.chromium.org/2355583002/

BUG=skia:
GOLD_TRYBOT_URL= https://gold.skia.org/search?issue=2355483002

Review-Url: https://codereview.chromium.org/2355483002
diff --git a/tests/DrawPathTest.cpp b/tests/DrawPathTest.cpp
index 9038406..87d51b1 100644
--- a/tests/DrawPathTest.cpp
+++ b/tests/DrawPathTest.cpp
@@ -339,7 +339,7 @@
     };
     SkRRect rr;
     rr.setRectRadii(r, radii);
-    canvas->clipRRect(rr, SkRegion::kIntersect_Op, false);
+    canvas->clipRRect(rr);
 
     SkRect r2 = SkRect::MakeLTRB(0, 33, 1102, 33554464);
     canvas->drawRect(r2, p);