CSSValue Immediates: Replace CSSPrimitiveValue usage with const references

Source/core/animation/DeferredLegacyStyleInterpolation.h

Index: Source/core/animation/DeferredLegacyStyleInterpolation.h
diff --git a/Source/core/animation/DeferredLegacyStyleInterpolation.h b/Source/core/animation/DeferredLegacyStyleInterpolation.h
index fa4f18a4f4076d8c07800c66fb72d87387597689..ef94a301cda8cb9b18c7de97877808256c45c830 100644
--- a/Source/core/animation/DeferredLegacyStyleInterpolation.h
+++ b/Source/core/animation/DeferredLegacyStyleInterpolation.h
@@ -21,7 +21,7 @@ class CSSValueList;
 
 class CORE_EXPORT DeferredLegacyStyleInterpolation : public StyleInterpolation {
 public:
-    static PassRefPtrWillBeRawPtr<DeferredLegacyStyleInterpolation> create(NullableCSSValue start, NullableCSSValue end, CSSPropertyID id)
+    static PassRefPtrWillBeRawPtr<DeferredLegacyStyleInterpolation> create(const NullableCSSValue& start, const NullableCSSValue& end, CSSPropertyID id)
     {
         return adoptRefWillBeNoop(new DeferredLegacyStyleInterpolation(start, end, id));
     }
@@ -30,8 +30,8 @@ public:
 
     DECLARE_VIRTUAL_TRACE();
 
-    static bool interpolationRequiresStyleResolve(const CSSValue);
-    static bool interpolationRequiresStyleResolve(const CSSPrimitiveValue);
+    static bool interpolationRequiresStyleResolve(const CSSValue&);
+    static bool interpolationRequiresStyleResolve(const CSSPrimitiveValue&);
     static bool interpolationRequiresStyleResolve(const CSSImageValue&);
     static bool interpolationRequiresStyleResolve(const CSSShadowValue&);
     static bool interpolationRequiresStyleResolve(const CSSSVGDocumentValue&);
@@ -43,7 +43,7 @@ public:
     virtual bool isDeferredLegacyStyleInterpolation() const override final { return true; }
 
 private:
-    DeferredLegacyStyleInterpolation(NullableCSSValue start, NullableCSSValue end, CSSPropertyID id)
+    DeferredLegacyStyleInterpolation(const NullableCSSValue& start, const NullableCSSValue& end, CSSPropertyID id)
         : StyleInterpolation(InterpolableNumber::create(0), InterpolableNumber::create(1), id)
         , m_startCSSValue(start)
         , m_endCSSValue(end)