Use SkTileMode instead of nested enum

Add guard to transition clients

Change-Id: Ia7a3e8f95722f91e84af262168dadf89a78707da
Reviewed-on: https://skia-review.googlesource.com/c/skia/+/205720
Reviewed-by: Mike Reed <reed@google.com>
Commit-Queue: Mike Reed <reed@google.com>
Auto-Submit: Mike Reed <reed@google.com>
diff --git a/gm/convexpolyclip.cpp b/gm/convexpolyclip.cpp
index e18de26..d531b66 100644
--- a/gm/convexpolyclip.cpp
+++ b/gm/convexpolyclip.cpp
@@ -50,7 +50,7 @@
                         pt, radius,
                         colors, pos,
                         SK_ARRAY_COUNT(colors),
-                        SkShader::kRepeat_TileMode,
+                        SkTileMode::kRepeat,
                         0, &mat));
         canvas.drawRect(rect, paint);
         rect.inset(wScalar / 8, hScalar / 8);