Add type casts for KeyframeEffectReadOnly

third_party/WebKit/Source/core/animation/KeyframeEffectReadOnly.h

 // Copyright 2016 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #ifndef KeyframeEffectReadOnly_h
 #define KeyframeEffectReadOnly_h
 
 #include "core/CoreExport.h"
 #include "core/animation/AnimationEffectReadOnly.h"
 #include "core/animation/EffectModel.h"
@@ skipping 28 matching lines @@
       const KeyframeEffectOptions& timingInput,
       ExceptionState&);
   static KeyframeEffectReadOnly* create(
       ExecutionContext*,
       Element*,
       const DictionarySequenceOrDictionary& effectInput,
       ExceptionState&);
 
   ~KeyframeEffectReadOnly() override {}
 
+  bool isKeyframeEffectReadOnly() const override { return true; }
+
   Priority getPriority() const { return m_priority; }
   void downgradeToNormal() { m_priority = DefaultPriority; }
 
   DECLARE_VIRTUAL_TRACE();
 
  protected:
   KeyframeEffectReadOnly(Element*,
                          EffectModel*,
                          const Timing&,
                          Priority,
                          EventDelegate*);
 
   Member<Element> m_target;
   Member<EffectModel> m_model;
   Member<SampledEffect> m_sampledEffect;
 
   Priority m_priority;
 };
 
+// TODO(suzyh): Replace calls to toKeyframeEffect with toKeyframeEffectReadOnly
+// where possible
+DEFINE_TYPE_CASTS(KeyframeEffectReadOnly,
+                  AnimationEffectReadOnly,
+                  animationNode,
+                  animationNode->isKeyframeEffectReadOnly(),
+                  animationNode.isKeyframeEffectReadOnly());
+
 }  // namespace blink
 
 #endif  // KeyframeEffectReadOnly_h