revised strokerect gm

include/core/SkScalar.h

Index: include/core/SkScalar.h
diff --git a/include/core/SkScalar.h b/include/core/SkScalar.h
index 4efa8417afd4a9edc903c19412a68ac3b997d7af..26352d1194191b4c7aace5faea9ef36d6731a01d 100644
--- a/include/core/SkScalar.h
+++ b/include/core/SkScalar.h
@@ -168,6 +168,18 @@ static inline int SkDScalarRoundToInt(SkScalar x) {
     return (int)floor(xx);
 }
 
+/**
+  * Variant of SkScalarRoundToInt, identical to SkDScalarRoundToInt except when the input fraction
+  * is 0.5. In this case only, round the value down. This is used to round the top and left
+  * of a rectangle, and corresponds to the way the scan converter treats the top and left edges.
+  */
+static inline int SkDScalarRoundDownToInt(SkScalar x) {
+    double xx = x;
+    xx += 0.5;
+    double floorXX = floor(xx);
+    return (int)floorXX - (xx == floorXX);
+}
+
 static inline SkScalar SkScalarClampMax(SkScalar x, SkScalar max) {
     x = SkTMin(x, max);
     x = SkTMax<SkScalar>(x, 0);