CSSValue Immediates: Replace CSSValue usage with const references

Source/core/animation/ListStyleInterpolationTest.cpp

Index: Source/core/animation/ListStyleInterpolationTest.cpp
diff --git a/Source/core/animation/ListStyleInterpolationTest.cpp b/Source/core/animation/ListStyleInterpolationTest.cpp
index 7ab7642dcc8565cf7fbc60ba378da589e29dc19e..f6c622f0203e4392480f9aaab44a3905e8c98e83 100644
--- a/Source/core/animation/ListStyleInterpolationTest.cpp
+++ b/Source/core/animation/ListStyleInterpolationTest.cpp
@@ -26,8 +26,8 @@ protected:
         ASSERT(actualList.isValueList());
 
         for (size_t i = 0; i < 10; i++) {
-            CSSValue currentExpectedValue = expectedList->item(i);
-            CSSValue currentActualValue = toCSSValueList(actualList).item(i);
+            const CSSValue& currentExpectedValue = expectedList->item(i);
+            const CSSValue& currentActualValue = toCSSValueList(actualList).item(i);
             ASSERT(currentExpectedValue.isPrimitiveValue());
             ASSERT(currentActualValue.isPrimitiveValue());