change flattenable factory to return sk_sp

src/effects/gradients/SkRadialGradient.cpp

Index: src/effects/gradients/SkRadialGradient.cpp
diff --git a/src/effects/gradients/SkRadialGradient.cpp b/src/effects/gradients/SkRadialGradient.cpp
index 1312b3692781e311f5cb48ab72f218c8f52d631e..e666ac3cbd0d71baa7c33c2cc0767f9706ef3d0b 100644
--- a/src/effects/gradients/SkRadialGradient.cpp
+++ b/src/effects/gradients/SkRadialGradient.cpp
@@ -60,7 +60,7 @@ SkShader::GradientType SkRadialGradient::asAGradient(GradientInfo* info) const {
     return kRadial_GradientType;
 }
 
-SkFlattenable* SkRadialGradient::CreateProc(SkReadBuffer& buffer) {
+sk_sp<SkFlattenable> SkRadialGradient::CreateProc(SkReadBuffer& buffer) {
     DescriptorScope desc;
     if (!desc.unflatten(buffer)) {
         return nullptr;
@@ -68,8 +68,7 @@ SkFlattenable* SkRadialGradient::CreateProc(SkReadBuffer& buffer) {
     const SkPoint center = buffer.readPoint();
     const SkScalar radius = buffer.readScalar();
     return SkGradientShader::MakeRadial(center, radius, desc.fColors, desc.fPos, desc.fCount,
-                                        desc.fTileMode, desc.fGradFlags,
-                                        desc.fLocalMatrix).release();
+                                        desc.fTileMode, desc.fGradFlags, desc.fLocalMatrix);
 }
 
 void SkRadialGradient::flatten(SkWriteBuffer& buffer) const {