Revert of Delete SkFlattenable::Type

src/utils/SkBitmapSourceDeserializer.h

 /*
  * Copyright 2015 Google Inc.
  *
  * Use of this source code is governed by a BSD-style license that can be
  * found in the LICENSE file.
  */
 
 #ifndef SkBitmapSourceDeserializer_DEFINED
 #define SkBitmapSourceDeserializer_DEFINED
 
 #include "SkFlattenable.h"
 
 // A temporary utility class to support deserializing legacy SkBitmapSource as SkImageSource.
 // Should be removed when SKP versions which may contain SkBitmapSource records are phased out.
 class SkBitmapSourceDeserializer : public SkFlattenable {
 public:
+    SK_DEFINE_FLATTENABLE_TYPE(SkImageFilter)
     SK_DECLARE_PUBLIC_FLATTENABLE_DESERIALIZATION_PROCS(SkBitmapSource)
 };
 
 #endif