Web Animations API: Deferred computation of interpolated values

Source/core/animation/InterpolableValuePromise.h

Index: Source/core/animation/InterpolableValuePromise.h
diff --git a/Source/core/animation/InterpolableValuePromise.h b/Source/core/animation/InterpolableValuePromise.h
new file mode 100644
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+++ b/Source/core/animation/InterpolableValuePromise.h
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+// 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 InterpolableValuePromise_h
+#define InterpolableValuePromise_h
+
+#include "CSSPropertyNames.h"
+#include "core/animation/InterpolableValue.h"
+
+namespace WebCore {
+
+class CSSPrimitiveValue;
+class Element;
+class StyleResolverState;
+
+class InterpolableValuePromise : public RefCountedWillBeGarbageCollected<InterpolableValuePromise> {
+    DECLARE_EMPTY_VIRTUAL_DESTRUCTOR_WILL_BE_REMOVED(InterpolableValuePromise);
+public:
+    // FIXME: remove element reference
+    static PassRefPtrWillBeRawPtr<InterpolableValuePromise> create(Element& element, CSSPropertyID id, PassRefPtrWillBeRawPtr<CSSValue> value)
+    {
+        return adoptRefWillBeNoop(new InterpolableValuePromise(element, id, value));
+    }
+
+    virtual void trace(Visitor*);
+
+    PassOwnPtrWillBeRawPtr<InterpolableValue> extract(StyleResolverState&, CSSPropertyID);
+    PassRefPtrWillBeRawPtr<AnimatableValue> extractAnimatableValue();
+
+    static bool requiresLateBinding(const CSSValue&);
+    static bool requiresLateBinding(const CSSPrimitiveValue&);
+
+private:
+    InterpolableValuePromise(Element&, CSSPropertyID, PassRefPtrWillBeRawPtr<CSSValue>);
+
+    RefPtrWillBeMember<CSSValue> m_cssValue;
+    OwnPtrWillBeMember<InterpolableAnimatableValue> m_interpolableAnimatableValue;
+};
+
+}
+
+#endif