Revert[2] "remove SK_SUPPORT_LEGACY_CLIP_REGIONOPS"

This reverts commit a129dfef2aaab0b5995cdf1ab7b2cdd41c29cf72.

BUG=skia:

Change-Id: I717de6e5fcd4516aa684b014b1414b0f82ac2b91
Reviewed-on: https://skia-review.googlesource.com/5722
Commit-Queue: Mike Reed <reed@google.com>
Reviewed-by: Derek Sollenberger <djsollen@google.com>
diff --git a/gm/windowrectangles.cpp b/gm/windowrectangles.cpp
index 3949b3f..e277db6 100644
--- a/gm/windowrectangles.cpp
+++ b/gm/windowrectangles.cpp
@@ -43,20 +43,20 @@
 
     SkClipStack stack;
     stack.clipRect(SkRect::MakeXYWH(370.75, 80.25, 149, 100), SkMatrix::I(),
-                   SkCanvas::kDifference_Op, false);
+                   kDifference_SkClipOp, false);
     stack.clipRect(SkRect::MakeXYWH(80.25, 420.75, 150, 100), SkMatrix::I(),
-                   SkCanvas::kDifference_Op, true);
+                   kDifference_SkClipOp, true);
     stack.clipRRect(SkRRect::MakeRectXY(SkRect::MakeXYWH(200, 200, 200, 200), 60, 45),
-                    SkMatrix::I(), SkCanvas::kDifference_Op, true);
+                    SkMatrix::I(), kDifference_SkClipOp, true);
 
     SkRRect nine;
     nine.setNinePatch(SkRect::MakeXYWH(550 - 30.25 - 100, 370.75, 100, 150), 12, 35, 23, 20);
-    stack.clipRRect(nine, SkMatrix::I(), SkCanvas::kDifference_Op, true);
+    stack.clipRRect(nine, SkMatrix::I(), kDifference_SkClipOp, true);
 
     SkRRect complx;
     SkVector complxRadii[4] = {{6, 4}, {8, 12}, {16, 24}, {48, 32}};
     complx.setRectRadii(SkRect::MakeXYWH(80.25, 80.75, 100, 149), complxRadii);
-    stack.clipRRect(complx, SkMatrix::I(), SkCanvas::kDifference_Op, false);
+    stack.clipRRect(complx, SkMatrix::I(), kDifference_SkClipOp, false);
 
     this->onCoverClipStack(stack, canvas);
 
@@ -79,7 +79,7 @@
  */
 class ReplayClipStackVisitor final : public SkCanvasClipVisitor {
 public:
-    typedef SkCanvas::ClipOp Op;
+    typedef SkClipOp Op;
     ReplayClipStackVisitor(SkCanvas* canvas) : fCanvas(canvas) {}
     void clipRect(const SkRect& r, Op op, bool aa) override { fCanvas->clipRect(r, op, aa); }
     void clipRRect(const SkRRect& rr, Op op, bool aa) override { fCanvas->clipRRect(rr, op, aa); }