Web Animations API: Deferred computation of interpolated values

Source/core/animation/InterpolableValue.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 InterpolableValue_h
 #define InterpolableValue_h
 
 #include "core/animation/AnimatableValue.h"
 #include "wtf/OwnPtr.h"
 #include "wtf/PassOwnPtr.h"
@@ skipping 10 matching lines @@
     virtual bool isAnimatableValue() const { return false; }
 
     virtual PassOwnPtrWillBeRawPtr<InterpolableValue> clone() const = 0;
 
     virtual void trace(Visitor*) { }
 
 private:
     virtual PassOwnPtrWillBeRawPtr<InterpolableValue> interpolate(const InterpolableValue &to, const double progress) const = 0;
 
     friend class Interpolation;
+    friend class LegacyStyleInterpolation;
 
     // Keep interpolate private, but allow calls within the hierarchy without
     // knowledge of type.
     friend class InterpolableNumber;
     friend class InterpolableBool;
     friend class InterpolableList;
 };
 
 class InterpolableNumber : public InterpolableValue {
 public:
@@ skipping 116 matching lines @@
 };
 
 DEFINE_TYPE_CASTS(InterpolableNumber, InterpolableValue, value, value->isNumber(), value.isNumber());
 DEFINE_TYPE_CASTS(InterpolableBool, InterpolableValue, value, value->isBool(), value.isBool());
 DEFINE_TYPE_CASTS(InterpolableList, InterpolableValue, value, value->isList(), value.isList());
 DEFINE_TYPE_CASTS(InterpolableAnimatableValue, InterpolableValue, value, value->isAnimatableValue(), value.isAnimatableValue());
 
 }
 
 #endif