CSSValue Immediates: Replace CSSPrimitiveValue usage with const references

Source/core/animation/ConstantStyleInterpolation.h

Index: Source/core/animation/ConstantStyleInterpolation.h
diff --git a/Source/core/animation/ConstantStyleInterpolation.h b/Source/core/animation/ConstantStyleInterpolation.h
index 936e37c7d5267f4927fafff5f93b4e4d6848ed1d..6ff60d3f855b4760a87288d0a13a061cb1e5697e 100644
--- a/Source/core/animation/ConstantStyleInterpolation.h
+++ b/Source/core/animation/ConstantStyleInterpolation.h
@@ -12,7 +12,7 @@ namespace blink {
 
 class ConstantStyleInterpolation : public StyleInterpolation {
 public:
-    static PassRefPtrWillBeRawPtr<ConstantStyleInterpolation> create(CSSValue value, CSSPropertyID id)
+    static PassRefPtrWillBeRawPtr<ConstantStyleInterpolation> create(const CSSValue& value, CSSPropertyID id)
     {
         return adoptRefWillBeNoop(new ConstantStyleInterpolation(value, id));
     }
@@ -29,7 +29,7 @@ public:
     }
 
 private:
-    ConstantStyleInterpolation(CSSValue value, CSSPropertyID id)
+    ConstantStyleInterpolation(const CSSValue& value, CSSPropertyID id)
         : StyleInterpolation(InterpolableList::create(0), InterpolableList::create(0), id)
         , m_value(value)
     { }