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

src/pdf/SkPDFCanvas.cpp

Index: src/pdf/SkPDFCanvas.cpp
diff --git a/src/pdf/SkPDFCanvas.cpp b/src/pdf/SkPDFCanvas.cpp
index 4ef1922a58fff23c86b315d6454d59208b769c9d..0fc242b3bfba2704b57543e705cca5b19d6fff7f 100644
--- a/src/pdf/SkPDFCanvas.cpp
+++ b/src/pdf/SkPDFCanvas.cpp
@@ -19,15 +19,15 @@ SkPDFCanvas::~SkPDFCanvas() {}
  *  we intercept all clip calls to ensure that the clip stays BW (i.e. never antialiased), since
  *  an antialiased clip won't build a SkRegion (it builds SkAAClip).
  */
-void SkPDFCanvas::onClipRect(const SkRect& rect, SkRegion::Op op, ClipEdgeStyle edgeStyle) {
+void SkPDFCanvas::onClipRect(const SkRect& rect, ClipOp op, ClipEdgeStyle edgeStyle) {
     this->INHERITED::onClipRect(rect, op, kHard_ClipEdgeStyle);
 }
 
-void SkPDFCanvas::onClipRRect(const SkRRect& rrect, SkRegion::Op op, ClipEdgeStyle edgeStyle) {
+void SkPDFCanvas::onClipRRect(const SkRRect& rrect, ClipOp op, ClipEdgeStyle edgeStyle) {
     this->INHERITED::onClipRRect(rrect, op, kHard_ClipEdgeStyle);
 }
 
-void SkPDFCanvas::onClipPath(const SkPath& path, SkRegion::Op op, ClipEdgeStyle edgeStyle) {
+void SkPDFCanvas::onClipPath(const SkPath& path, ClipOp op, ClipEdgeStyle edgeStyle) {
     this->INHERITED::onClipPath(path, op, kHard_ClipEdgeStyle);
 }