CSSValue Immediates: Replace CSSPrimitiveValue usage with const references

Source/core/css/StylePropertySet.cpp

Index: Source/core/css/StylePropertySet.cpp
diff --git a/Source/core/css/StylePropertySet.cpp b/Source/core/css/StylePropertySet.cpp
index 78d600fa42a745186c47def4ecc99be6b5d77c6e..6e432336a38860c0e1bcd89016a365c1c13c0437 100644
--- a/Source/core/css/StylePropertySet.cpp
+++ b/Source/core/css/StylePropertySet.cpp
@@ -137,19 +137,19 @@ MutableStylePropertySet::MutableStylePropertySet(const StylePropertySet& other)
 
 String StylePropertySet::getPropertyValue(CSSPropertyID propertyID) const
 {
-    NullableCSSValue value = getPropertyCSSValue(propertyID);
+    const NullableCSSValue& value = getPropertyCSSValue(propertyID);
     if (value)
         return value->cssText();
 
     return StylePropertySerializer(*this).getPropertyValue(propertyID);
 }
 
-NullableCSSValue StylePropertySet::getPropertyCSSValue(CSSPropertyID propertyID) const
+const NullableCSSValue StylePropertySet::getPropertyCSSValue(CSSPropertyID propertyID) const
 {
     int foundPropertyIndex = findPropertyIndex(propertyID);
     if (foundPropertyIndex == -1)
         return nullptr;
-    return propertyAt(foundPropertyIndex).value();
+    return *reinterpret_cast<const NullableCSSValue*>(&propertyAt(foundPropertyIndex).value());
 }
 
 DEFINE_TRACE(StylePropertySet)
@@ -439,7 +439,7 @@ PassRefPtrWillBeRawPtr<MutableStylePropertySet> StylePropertySet::copyProperties
     WillBeHeapVector<CSSProperty, 256> list;
     list.reserveInitialCapacity(properties.size());
     for (unsigned i = 0; i < properties.size(); ++i) {
-        NullableCSSValue value = getPropertyCSSValue(properties[i]);
+        const NullableCSSValue& value = getPropertyCSSValue(properties[i]);
         if (value)
             list.append(CSSProperty(properties[i], *value, false));
     }