change flattenable factory to return sk_sp

gm/dcshader.cpp

Index: gm/dcshader.cpp
diff --git a/gm/dcshader.cpp b/gm/dcshader.cpp
index 487f7671eef62c6b7f2be3e76f8afda3189d60c8..e402fc0c2b7ee69ea62749a2806b9383e5ee1d80 100644
--- a/gm/dcshader.cpp
+++ b/gm/dcshader.cpp
@@ -50,10 +50,10 @@ private:
     const SkMatrix fDeviceMatrix;
 };
 
-SkFlattenable* DCShader::CreateProc(SkReadBuffer& buf) {
+sk_sp<SkFlattenable> DCShader::CreateProc(SkReadBuffer& buf) {
     SkMatrix matrix;
     buf.readMatrix(&matrix);
-    return new DCShader(matrix);
+    return sk_make_sp<DCShader>(matrix);
 }
 
 class DCFP : public GrFragmentProcessor {