change flattenable factory to return sk_sp

src/core/SkColorFilter.cpp

Index: src/core/SkColorFilter.cpp
diff --git a/src/core/SkColorFilter.cpp b/src/core/SkColorFilter.cpp
index 3e0a2ec46f92eadead1b915ae59d8e968736250e..e3d89579471aa6f4c1cb82f18e04360ee08058fd 100644
--- a/src/core/SkColorFilter.cpp
+++ b/src/core/SkColorFilter.cpp
@@ -142,10 +142,10 @@ private:
     typedef SkColorFilter INHERITED;
 };
 
-SkFlattenable* SkComposeColorFilter::CreateProc(SkReadBuffer& buffer) {
+sk_sp<SkFlattenable> SkComposeColorFilter::CreateProc(SkReadBuffer& buffer) {
     sk_sp<SkColorFilter> outer(buffer.readColorFilter());
     sk_sp<SkColorFilter> inner(buffer.readColorFilter());
-    return MakeComposeFilter(std::move(outer), std::move(inner)).release();
+    return MakeComposeFilter(std::move(outer), std::move(inner));
 }
 
 ///////////////////////////////////////////////////////////////////////////////////////////////////