Enable interpolation of CSS property font-variation-settings

third_party/WebKit/Source/core/animation/CSSFontVariationSettingsInterpolationType.h

+// 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.
+
+#ifndef CSSFontVariationSettingsInterpolationType_h
+#define CSSFontVariationSettingsInterpolationType_h
+
+#include "core/animation/CSSInterpolationType.h"
+
+namespace blink {
+
+class CSSFontVariationSettingsInterpolationType : public CSSInterpolationType {
+ public:
+  CSSFontVariationSettingsInterpolationType(PropertyHandle property)
+      : CSSInterpolationType(property) {
+    DCHECK_EQ(CssProperty(), CSSPropertyFontVariationSettings);
+  }
+
+  InterpolationValue MaybeConvertStandardPropertyUnderlyingValue(
+      const ComputedStyle&) const final;
+  PairwiseInterpolationValue MaybeMergeSingles(
+      InterpolationValue&& start,
+      InterpolationValue&& end) const final;
+  void Composite(UnderlyingValueOwner&,
+                 double underlying_fraction,
+                 const InterpolationValue&,
+                 double interpolation_fraction) const final;
+  void ApplyStandardPropertyValue(const InterpolableValue&,
+                                  const NonInterpolableValue*,
+                                  StyleResolverState&) const final;
+
+ private:
+  InterpolationValue MaybeConvertNeutral(const InterpolationValue& underlying,
+                                         ConversionCheckers&) const final;
+  InterpolationValue MaybeConvertInitial(const StyleResolverState&,
+                                         ConversionCheckers&) const final;
+  InterpolationValue MaybeConvertInherit(const StyleResolverState&,
+                                         ConversionCheckers&) const final;
+  InterpolationValue MaybeConvertValue(const CSSValue&,
+                                       const StyleResolverState*,
+                                       ConversionCheckers&) const final;
+};
+
+}  // namespace blink
+
+#endif  // CSSFontVariationSettingsInterpolationType_h