Remove AtomicStringImpl.

Source/core/css/StyleInvalidationAnalysis.h

Index: Source/core/css/StyleInvalidationAnalysis.h
diff --git a/Source/core/css/StyleInvalidationAnalysis.h b/Source/core/css/StyleInvalidationAnalysis.h
index 18dad9f6e24891500f998ed8b3f5e9036302c77a..e58f37a672ba670e535367bb8bb797f1fa7f5235 100644
--- a/Source/core/css/StyleInvalidationAnalysis.h
+++ b/Source/core/css/StyleInvalidationAnalysis.h
@@ -28,7 +28,7 @@
 
 #include "wtf/HashSet.h"
 #include "wtf/Vector.h"
-#include "wtf/text/AtomicStringImpl.h"
+#include "wtf/text/StringImpl.h"
 
 namespace WebCore {
 
@@ -48,8 +48,8 @@ private:
     void analyzeStyleSheet(StyleSheetContents*);
 
     bool m_dirtiesAllStyle;
-    HashSet<AtomicStringImpl*> m_idScopes;
-    HashSet<AtomicStringImpl*> m_classScopes;
+    HashSet<StringImpl*> m_idScopes;
+    HashSet<StringImpl*> m_classScopes;
     Vector<Node*, 8> m_scopingNodes;
 };