Don't create a GXPFactory when blend is SrcOver

src/gpu/batches/GrDefaultPathRenderer.cpp

Index: src/gpu/batches/GrDefaultPathRenderer.cpp
diff --git a/src/gpu/batches/GrDefaultPathRenderer.cpp b/src/gpu/batches/GrDefaultPathRenderer.cpp
index d0777e253fa70332ee36988fe5c0685a2506acd7..fa2ffe0b4df0e1b170a76088769eac5e1ce5f233 100644
--- a/src/gpu/batches/GrDefaultPathRenderer.cpp
+++ b/src/gpu/batches/GrDefaultPathRenderer.cpp
@@ -564,7 +564,8 @@ bool GrDefaultPathRenderer::internalDrawPath(GrDrawTarget* target,
     const bool isHairline = stroke->isHairlineStyle();
 
     // Save the current xp on the draw state so we can reset it if needed
-    SkAutoTUnref<const GrXPFactory> backupXPFactory(SkRef(pipelineBuilder->getXPFactory()));
+    const GrXPFactory* xpFactory = pipelineBuilder->getXPFactory();
+    SkAutoTUnref<const GrXPFactory> backupXPFactory(SkSafeRef(xpFactory));
     // face culling doesn't make sense here
     SkASSERT(GrPipelineBuilder::kBoth_DrawFace == pipelineBuilder->getDrawFace());