Web Animations: Add InterpolableValue hierarchy.

Source/core/animation/InterpolableValue.cpp

+// 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.
+
+#include "config.h"
+#include "core/animation/InterpolableValue.h"
+
+namespace WebCore {
+
+PassOwnPtr<InterpolableValue> InterpolableNumber::interpolate(const InterpolableValue &to, const double progress) const
+{
+    const InterpolableNumber* toNumber = toInterpolableNumber(&to);
+    if (!progress)
+        return create(m_value);
+    if (progress == 1)
+        return create(toNumber->m_value);
+    return create(m_value * (1 - progress) + toNumber->m_value * progress);
+}
+
+PassOwnPtr<InterpolableValue> InterpolableBool::interpolate(const InterpolableValue &to, const double progress) const
+{
+    if (progress < 0.5) {
+        return clone();
+    }
+    return to.clone();
+}
+
+PassOwnPtr<InterpolableValue> InterpolableList::interpolate(const InterpolableValue &to, const double progress) const
+{
+    const InterpolableList* toList = toInterpolableList(&to);
+    ASSERT(toList->m_size == m_size);
+
+    if (!progress) {
+        return create(*this);
+    }
+    if (progress == 1) {
+        return InterpolableList::create(*toList);
+    }
+
+    OwnPtr<InterpolableList> result = create(m_size);
+    for (size_t i = 0; i < m_size; i++) {
+        ASSERT(m_values.get()[i]);
+        ASSERT(toList->m_values.get()[i]);
+        result->set(i, m_values.get()[i]->interpolate(*(toList->m_values.get()[i]), progress));
+    }
+    return result.release();
+}
+
+}