compute convexity for very small paths

src/core/SkStroke.cpp

Index: src/core/SkStroke.cpp
diff --git a/src/core/SkStroke.cpp b/src/core/SkStroke.cpp
index 86c0571c4b8fd618827999a5ec07513affc3a332..d21dc9671338f4beb168661987865b62699123a1 100644
--- a/src/core/SkStroke.cpp
+++ b/src/core/SkStroke.cpp
@@ -356,7 +356,7 @@ void SkPathStroker::line_to(const SkPoint& currPt, const SkVector& normal) {
 }
 
 void SkPathStroker::lineTo(const SkPoint& currPt) {
-    if (SkPath::IsLineDegenerate(fPrevPt, currPt)) {
+    if (SkPath::IsLineDegenerate(fPrevPt, currPt, false)) {
         return;
     }
     SkVector    normal, unitNormal;