Combine {Legacy,}StyleInterpolation.h

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

Index: third_party/WebKit/Source/core/animation/LegacyStyleInterpolation.h
diff --git a/third_party/WebKit/Source/core/animation/LegacyStyleInterpolation.h b/third_party/WebKit/Source/core/animation/LegacyStyleInterpolation.h
index 5d9dc21c3c844be66792628313e759070bf17ab7..0a0d294e5e37197e2ab7a1733e6225c5a484b156 100644
--- a/third_party/WebKit/Source/core/animation/LegacyStyleInterpolation.h
+++ b/third_party/WebKit/Source/core/animation/LegacyStyleInterpolation.h
@@ -5,12 +5,49 @@
 #ifndef LegacyStyleInterpolation_h
 #define LegacyStyleInterpolation_h
 
-#include "core/animation/StyleInterpolation.h"
+#include "core/CSSPropertyNames.h"
+#include "core/CoreExport.h"
+#include "core/animation/Interpolation.h"
+#include "core/animation/PropertyHandle.h"
 #include "core/css/resolver/AnimatedStyleBuilder.h"
 #include <memory>
 
 namespace blink {
 
+class StyleResolverState;
+
+class CORE_EXPORT StyleInterpolation : public Interpolation {
+ public:
+  // 1) convert m_cachedValue into an X
+  // 2) shove X into StyleResolverState
+  // X can be:
+  // (1) a CSSValue (and applied via StyleBuilder::applyProperty)
+  // (2) an AnimatableValue (and applied via
+  //     AnimatedStyleBuilder::applyProperty)
+  // (3) a custom value that is inserted directly into the StyleResolverState.
+  virtual void apply(StyleResolverState&) const = 0;
+
+  bool isStyleInterpolation() const final { return true; }
+
+  CSSPropertyID id() const { return m_id; }
+
+  PropertyHandle getProperty() const final { return PropertyHandle(id()); }
+
+ protected:
+  CSSPropertyID m_id;
+
+  StyleInterpolation(std::unique_ptr<InterpolableValue> start,
+                     std::unique_ptr<InterpolableValue> end,
+                     CSSPropertyID id)
+      : Interpolation(std::move(start), std::move(end)), m_id(id) {}
+};
+
+DEFINE_TYPE_CASTS(StyleInterpolation,
+                  Interpolation,
+                  value,
+                  value->isStyleInterpolation(),
+                  value.isStyleInterpolation());
+
 class LegacyStyleInterpolation : public StyleInterpolation {
  public:
   static PassRefPtr<LegacyStyleInterpolation> create(