Web Animations API: Deferred computation of interpolated values

Source/core/animation/LegacyStyleInterpolation.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 LegacyStyleInterpolation_h
+#define LegacyStyleInterpolation_h
+
+#include "core/animation/Interpolation.h"
+
+namespace WebCore {
+
+class CSSPrimitiveValue;
+class Element;
+
+class LegacyStyleInterpolation : public StyleInterpolation {
+public:
+    static PassRefPtrWillBeRawPtr<LegacyStyleInterpolation> create(CSSValue& start, CSSValue& end, CSSPropertyID, Element&);
+    static PassRefPtrWillBeRawPtr<LegacyStyleInterpolation> create(PassOwnPtrWillBeRawPtr<InterpolableAnimatableValue> start, PassOwnPtrWillBeRawPtr<InterpolableAnimatableValue> end, CSSPropertyID id)
+    {
+        return adoptRefWillBeNoop(new LegacyStyleInterpolation(start, end, id));
+    }
+
+    virtual void apply(StyleResolverState&) const OVERRIDE;
+
+    virtual bool isLegacyStyleInterpolation() const OVERRIDE FINAL { return true; }
+
+    PassRefPtrWillBeRawPtr<AnimatableValue> currentValue() const
+    {
+        if (m_interpolationRequiresStyleResolve)
+            return nullptr;
+        return toInterpolableAnimatableValue(*m_cachedValue).value();
+    }
+
+    static bool interpolationRequiresStyleResolve(const CSSValue&);
+    static bool interpolationRequiresStyleResolve(const CSSPrimitiveValue&);
+
+    virtual void trace(Visitor*) OVERRIDE;
+
+private:
+    LegacyStyleInterpolation(PassOwnPtrWillBeRawPtr<InterpolableAnimatableValue> start, PassOwnPtrWillBeRawPtr<InterpolableAnimatableValue> end, CSSPropertyID id)
+        : StyleInterpolation(start, end, id)
+        , m_interpolationRequiresStyleResolve(false)
+    {
+    }
+
+    LegacyStyleInterpolation(PassRefPtrWillBeRawPtr<CSSValue> start, PassRefPtrWillBeRawPtr<CSSValue> end, CSSPropertyID id)
+        : StyleInterpolation(InterpolableNumber::create(0), InterpolableNumber::create(1), id)
+        , m_interpolationRequiresStyleResolve(true)
+        , m_startCSSValue(start)
+        , m_endCSSValue(end)
+    {
+    }
+
+    const bool m_interpolationRequiresStyleResolve;
+    const RefPtrWillBeMember<CSSValue> m_startCSSValue;
+    const RefPtrWillBeMember<CSSValue> m_endCSSValue;
+};
+
+DEFINE_TYPE_CASTS(LegacyStyleInterpolation, Interpolation, value, value->isLegacyStyleInterpolation(), value.isLegacyStyleInterpolation());
+
+}
+
+#endif