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/complexclip_blur_tiled.cpp b/gm/complexclip_blur_tiled.cpp
index 31db174..3a0f0e0 100644
--- a/gm/complexclip_blur_tiled.cpp
+++ b/gm/complexclip_blur_tiled.cpp
@@ -52,7 +52,7 @@
                 SkRect rect = SkRect::MakeWH(WIDTH, HEIGHT);
                 tileCanvas->saveLayer(&rect, &blurPaint);
                 SkRRect rrect = SkRRect::MakeRectXY(rect.makeInset(20, 20), 25, 25);
-                tileCanvas->clipRRect(rrect, SkCanvas::kDifference_Op, true);
+                tileCanvas->clipRRect(rrect, kDifference_SkClipOp, true);
                 SkPaint paint;
                 tileCanvas->drawRect(rect, paint);
                 tileCanvas->restore();