Analytic rrect clip for cicular corners, radius >= .5

include/core/SkRRect.h

Index: include/core/SkRRect.h
diff --git a/include/core/SkRRect.h b/include/core/SkRRect.h
index e70cff6db9a5ea80f49af4057be1b2aff65dbe12..141a3d27afc98e0ed5692cae076e2f616362fbdc 100644
--- a/include/core/SkRRect.h
+++ b/include/core/SkRRect.h
@@ -96,6 +96,9 @@ public:
     inline bool isRect() const { return kRect_Type == this->getType(); }
     inline bool isOval() const { return kOval_Type == this->getType(); }
     inline bool isSimple() const { return kSimple_Type == this->getType(); }
+    inline bool isSimpleCircular() const {
+        return this->isSimple() && fRadii[0].fX == fRadii[0].fY;
+    }
     inline bool isComplex() const { return kComplex_Type == this->getType(); }
 
     SkScalar width() const { return fRect.width(); }