Add gm that tests shaded stroked rectangles.

src/gpu/effects/GrDashingEffect.cpp

Index: src/gpu/effects/GrDashingEffect.cpp
diff --git a/src/gpu/effects/GrDashingEffect.cpp b/src/gpu/effects/GrDashingEffect.cpp
index ae375409cb8c54620d713957c640203e497ca527..4e82a62195c4d92ef2d705e1a5297d3c2a19972e 100644
--- a/src/gpu/effects/GrDashingEffect.cpp
+++ b/src/gpu/effects/GrDashingEffect.cpp
@@ -1240,7 +1240,7 @@ DRAW_BATCH_TEST_DEFINE(DashBatch) {
     }
 
     // pick random cap
-    SkPaint::Cap cap = SkPaint::Cap(random->nextULessThan(SkPaint::Cap::kCapCount));
+    SkPaint::Cap cap = SkPaint::Cap(random->nextULessThan(SkPaint::kCapCount));
 
     SkScalar intervals[2];