Make Sk2DPathEffect thread safe.

src/effects/Sk2DPathEffect.cpp

Index: src/effects/Sk2DPathEffect.cpp
diff --git a/src/effects/Sk2DPathEffect.cpp b/src/effects/Sk2DPathEffect.cpp
index 52e3fa5e1c88b63d3f7c797a5ab736a7e8feb81f..e7ef54b6f7a947c792c2c8b5ebc6113f394507a7 100644
--- a/src/effects/Sk2DPathEffect.cpp
+++ b/src/effects/Sk2DPathEffect.cpp
@@ -14,7 +14,8 @@
 #include "SkStrokeRec.h"
 
 Sk2DPathEffect::Sk2DPathEffect(const SkMatrix& mat) : fMatrix(mat) {
-    fMatrixIsInvertible = mat.invert(&fInverse);
+    // Calling invert will set the type mask on both matrices, making them thread safe.
+    fMatrixIsInvertible = fMatrix.invert(&fInverse);
 }
 
 bool Sk2DPathEffect::filterPath(SkPath* dst, const SkPath& src,