Fix unit tests

Review URL: https://codereview.chromium.org/197823002

git-svn-id: http://skia.googlecode.com/svn/trunk@13772 2bbb7eff-a529-9590-31e7-b0007b416f81
diff --git a/src/gpu/effects/GrRRectEffect.cpp b/src/gpu/effects/GrRRectEffect.cpp
index d766963..636730d 100644
--- a/src/gpu/effects/GrRRectEffect.cpp
+++ b/src/gpu/effects/GrRRectEffect.cpp
@@ -455,7 +455,8 @@
     rrect.setRectXY(SkRect::MakeWH(w, h), rx, ry);
     GrEffectRef* effect;
     do {
-        GrEffectEdgeType et = (GrEffectEdgeType)random->nextULessThan(kGrEffectEdgeTypeCnt);
+        GrEffectEdgeType et = random->nextBool() ? kFillAA_GrEffectEdgeType : 
+                                                   kInverseFillAA_GrEffectEdgeType;
         effect = EllipticalRRectEffect::Create(et, rrect);
     } while (NULL == effect);
     return effect;