change flattenable factory to return sk_sp

src/core/SkModeColorFilter.cpp

Index: src/core/SkModeColorFilter.cpp
diff --git a/src/core/SkModeColorFilter.cpp b/src/core/SkModeColorFilter.cpp
index 84c6491f3aab7f90253105598ddd22438b481af2..eacd261b5cb97eccecbfde904c29f817359d2058 100644
--- a/src/core/SkModeColorFilter.cpp
+++ b/src/core/SkModeColorFilter.cpp
@@ -77,10 +77,10 @@ void SkModeColorFilter::updateCache() {
     fProc = SkXfermode::GetProc(fMode);
 }
 
-SkFlattenable* SkModeColorFilter::CreateProc(SkReadBuffer& buffer) {
+sk_sp<SkFlattenable> SkModeColorFilter::CreateProc(SkReadBuffer& buffer) {
     SkColor color = buffer.readColor();
     SkXfermode::Mode mode = (SkXfermode::Mode)buffer.readUInt();
-    return SkColorFilter::MakeModeFilter(color, mode).release();
+    return SkColorFilter::MakeModeFilter(color, mode);
 }
 
 ///////////////////////////////////////////////////////////////////////////////