Add quad to cubic bezier conversion utility to SkPath.

src/core/SkPath.cpp

Index: src/core/SkPath.cpp
diff --git a/src/core/SkPath.cpp b/src/core/SkPath.cpp
index ab8d7359d2271b5a15b531859f44379522a4b378..0928dfe7a7d5528898df8fed1d3d2c8645158115 100644
--- a/src/core/SkPath.cpp
+++ b/src/core/SkPath.cpp
@@ -3094,3 +3094,7 @@ int SkPath::ConvertConicToQuads(const SkPoint& p0, const SkPoint& p1, const SkPo
     const SkConic conic(p0, p1, p2, w);
     return conic.chopIntoQuadsPOW2(pts, pow2);
 }
+
+void SkPath::ConvertQuadToCubic(const SkPoint src[3], SkPoint dst[4]) {
+    SkConvertQuadToCubic(src, dst);
+}