guard rasterizer and drawlooper setters

src/core/SkReadBuffer.h

Index: src/core/SkReadBuffer.h
diff --git a/src/core/SkReadBuffer.h b/src/core/SkReadBuffer.h
index c7ac8480eceddbeb35d5b475620a8a866dd60710..575375edede670cbb56d4dd4d63cb2d2a6775755 100644
--- a/src/core/SkReadBuffer.h
+++ b/src/core/SkReadBuffer.h
@@ -131,13 +131,17 @@ public:
         return (T*) this->readFlattenable(T::GetFlattenableType());
     }
     SkColorFilter* readColorFilter() { return this->readFlattenable<SkColorFilter>(); }
-    SkDrawLooper*  readDrawLooper()  { return this->readFlattenable<SkDrawLooper>(); }
+    sk_sp<SkDrawLooper> readDrawLooper() {
+        return sk_sp<SkDrawLooper>(this->readFlattenable<SkDrawLooper>());
+    }
     SkImageFilter* readImageFilter() { return this->readFlattenable<SkImageFilter>(); }
     SkMaskFilter*  readMaskFilter()  { return this->readFlattenable<SkMaskFilter>(); }
     sk_sp<SkPathEffect> readPathEffect()  {
         return sk_sp<SkPathEffect>(this->readFlattenable<SkPathEffect>());
     }
-    SkRasterizer*  readRasterizer()  { return this->readFlattenable<SkRasterizer>(); }
+    sk_sp<SkRasterizer> readRasterizer() {
+        return sk_sp<SkRasterizer>(this->readFlattenable<SkRasterizer>());
+    }
     sk_sp<SkShader> readShader()     { return sk_sp<SkShader>(this->readFlattenable<SkShader>()); }
     SkXfermode*    readXfermode()    { return this->readFlattenable<SkXfermode>(); }