include RefCounted.h where needed, only.

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

 // Copyright 2014 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 Keyframe_h
 #define Keyframe_h
 
 #include "core/CoreExport.h"
 #include "core/animation/AnimationEffect.h"
 #include "core/animation/EffectModel.h"
 #include "core/animation/PropertyHandle.h"
 #include "core/animation/animatable/AnimatableValue.h"
 #include "wtf/Allocator.h"
+#include "wtf/Forward.h"
+#include "wtf/RefCounted.h"
+#include "wtf/RefPtr.h"
 
 namespace blink {
 
 using PropertyHandleSet = HashSet<PropertyHandle>;
 
 class Element;
 class ComputedStyle;
 
 // Represents a user specificed keyframe in a KeyframeEffect.
 // http://w3c.github.io/web-animations/#keyframe
@@ skipping 82 matching lines @@
     double m_offset;
     EffectModel::CompositeOperation m_composite;
     RefPtr<TimingFunction> m_easing;
 };
 
 using PropertySpecificKeyframe = Keyframe::PropertySpecificKeyframe;
 
 } // namespace blink
 
 #endif // Keyframe_h