Make CSSProperty store a const CSSValue

third_party/WebKit/Source/core/css/CSSProperty.h

Index: third_party/WebKit/Source/core/css/CSSProperty.h
diff --git a/third_party/WebKit/Source/core/css/CSSProperty.h b/third_party/WebKit/Source/core/css/CSSProperty.h
index fb1dc8832de72d3866ec9efcfeba86c68c1f62fc..1af11dea508561d78de359a6783a630160f859af 100644
--- a/third_party/WebKit/Source/core/css/CSSProperty.h
+++ b/third_party/WebKit/Source/core/css/CSSProperty.h
@@ -58,14 +58,14 @@ struct StylePropertyMetadata {
 class CSSProperty {
     DISALLOW_NEW_EXCEPT_PLACEMENT_NEW();
 public:
-    CSSProperty(CSSPropertyID propertyID, CSSValue* value, bool important = false, bool isSetFromShorthand = false, int indexInShorthandsVector = 0, bool implicit = false)
+    CSSProperty(CSSPropertyID propertyID, const CSSValue* value, bool important = false, bool isSetFromShorthand = false, int indexInShorthandsVector = 0, bool implicit = false)
         : m_metadata(propertyID, isSetFromShorthand, indexInShorthandsVector, important, implicit, CSSPropertyMetadata::isInheritedProperty(propertyID))
         , m_value(value)
     {
     }
 
     // FIXME: Remove this.
-    CSSProperty(StylePropertyMetadata metadata, CSSValue* value)
+    CSSProperty(StylePropertyMetadata metadata, const CSSValue* value)
         : m_metadata(metadata)
         , m_value(value)
     {
@@ -76,7 +76,7 @@ public:
     CSSPropertyID shorthandID() const { return m_metadata.shorthandID(); }
     bool isImportant() const { return m_metadata.m_important; }
 
-    CSSValue* value() const { return m_value.get(); }
+    const CSSValue* value() const { return m_value.get(); }
 
     static CSSPropertyID resolveDirectionAwareProperty(CSSPropertyID, TextDirection, WritingMode);
     static bool isAffectedByAllProperty(CSSPropertyID);
@@ -89,7 +89,7 @@ public:
 
 private:
     StylePropertyMetadata m_metadata;
-    Member<CSSValue> m_value;
+    Member<const CSSValue> m_value;
 };
 
 } // namespace blink