Add ComputedStyle constructor and getter to InterpolationEnvironment

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

+// Copyright 2016 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/InterpolationEnvironment.h"
+
+#include "core/css/resolver/StyleResolverState.h"
+
+namespace blink {
+
+InterpolationEnvironment::InterpolationEnvironment(StyleResolverState& state)
+    : m_state(&state)
+    , m_style(state.style())
+    , m_svgElement(nullptr)
+    , m_svgBaseValue(nullptr)
+{
+}
+
+ComputedStyle& InterpolationEnvironment::style()
+{
+    return *state().style();
+}
+
+} // namespace blink