Add TransitionInterpolation class for CSS Transition refactor

third_party/WebKit/Source/core/animation/TransitionInterpolation.cpp

Index: third_party/WebKit/Source/core/animation/TransitionInterpolation.cpp
diff --git a/third_party/WebKit/Source/core/animation/TransitionInterpolation.cpp b/third_party/WebKit/Source/core/animation/TransitionInterpolation.cpp
new file mode 100644
index 0000000000000000000000000000000000000000..7bb4384b6b19be7b61f0aff0c2a53170ea778794
--- /dev/null
+++ b/third_party/WebKit/Source/core/animation/TransitionInterpolation.cpp
@@ -0,0 +1,67 @@
+// Copyright 2017 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 "core/animation/TransitionInterpolation.h"
+
+#include "core/animation/CSSInterpolationTypesMap.h"
+#include "core/animation/InterpolationEnvironment.h"
+#include "core/animation/InterpolationType.h"
+#include "core/css/resolver/StyleResolverState.h"
+
+namespace blink {
+
+void TransitionInterpolation::interpolate(int iteration, double fraction) {
+  if (m_cachedFraction != fraction || m_cachedIteration != iteration) {
+    if (fraction != 0 && fraction != 1) {
+      m_merge.startInterpolableValue->interpolate(
+          *m_merge.endInterpolableValue, fraction, *m_cachedInterpolableValue);
+    }
+    m_cachedIteration = iteration;
+    m_cachedFraction = fraction;
+  }
+}
+
+const InterpolableValue& TransitionInterpolation::currentInterpolableValue()
+    const {
+  if (m_cachedFraction == 0) {
+    return *m_start.interpolableValue;
+  }
+  if (m_cachedFraction == 1) {
+    return *m_end.interpolableValue;
+  }
+  return *m_cachedInterpolableValue;
+}
+
+NonInterpolableValue* TransitionInterpolation::currentNonInterpolableValue()
+    const {
+  if (m_cachedFraction == 0) {
+    return m_start.nonInterpolableValue.get();
+  }
+  if (m_cachedFraction == 1) {
+    return m_end.nonInterpolableValue.get();
+  }
+  return m_merge.nonInterpolableValue.get();
+}
+
+void TransitionInterpolation::apply(StyleResolverState& state) const {
+  CSSInterpolationTypesMap map(state.document().propertyRegistry());
+  InterpolationEnvironment environment(map, state);
+  m_type.apply(currentInterpolableValue(), currentNonInterpolableValue(),
+               environment);
+}
+
+std::unique_ptr<TypedInterpolationValue>
+TransitionInterpolation::getInterpolatedValue() const {
+  return TypedInterpolationValue::create(m_type,
+                                         currentInterpolableValue().clone(),
+                                         currentNonInterpolableValue());
+}
+
+RefPtr<AnimatableValue>
+TransitionInterpolation::getInterpolatedCompositorValue() const {
+  return AnimatableValue::interpolate(m_compositorStart.get(),
+                                      m_compositorEnd.get(), m_cachedFraction);
+}
+
+}  // namespace blink