change flattenable factory to return sk_sp

src/core/SkBitmapProcShader.cpp

Index: src/core/SkBitmapProcShader.cpp
diff --git a/src/core/SkBitmapProcShader.cpp b/src/core/SkBitmapProcShader.cpp
index 14114c08937bed7697a6ebf15f9fb23acbee0ff6..c9df4ce248c7c6d6b5a3f947f26aaa36b56d3065 100644
--- a/src/core/SkBitmapProcShader.cpp
+++ b/src/core/SkBitmapProcShader.cpp
@@ -275,7 +275,7 @@ bool SkBitmapProcShader::onIsABitmap(SkBitmap* texture, SkMatrix* texM, TileMode
     return true;
 }
 
-SkFlattenable* SkBitmapProcShader::CreateProc(SkReadBuffer& buffer) {
+sk_sp<SkFlattenable> SkBitmapProcShader::CreateProc(SkReadBuffer& buffer) {
     SkMatrix lm;
     buffer.readMatrix(&lm);
     SkBitmap bm;
@@ -285,7 +285,7 @@ SkFlattenable* SkBitmapProcShader::CreateProc(SkReadBuffer& buffer) {
     bm.setImmutable();
     TileMode mx = (TileMode)buffer.readUInt();
     TileMode my = (TileMode)buffer.readUInt();
-    return SkShader::MakeBitmapShader(bm, mx, my, &lm).release();
+    return SkShader::MakeBitmapShader(bm, mx, my, &lm);
 }
 
 void SkBitmapProcShader::flatten(SkWriteBuffer& buffer) const {