Remove AtomicStringImpl.

Source/core/css/RuleFeature.h

Index: Source/core/css/RuleFeature.h
diff --git a/Source/core/css/RuleFeature.h b/Source/core/css/RuleFeature.h
index c7b28ab7dbf8ac3ab3c379e3ef415d1dd84ba260..ed7f0d74ebd9a16647172cbbc3d979571cd9e8ce 100644
--- a/Source/core/css/RuleFeature.h
+++ b/Source/core/css/RuleFeature.h
@@ -59,22 +59,22 @@ public:
     bool usesFirstLineRules() const { return m_usesFirstLineRules; }
     bool usesBeforeAfterRules() const { return m_usesBeforeAfterRules; }
 
-    inline bool hasSelectorForAttribute(const AtomicString &attributeName) const
+    inline bool hasSelectorForAttribute(const AtomicString& attributeName) const
     {
         ASSERT(!attributeName.isEmpty());
-        return attrsInRules.contains(attributeName.impl());
+        return attrsInRules.contains(attributeName);
     }
 
     inline bool hasSelectorForClass(const AtomicString& classValue) const
     {
         ASSERT(!classValue.isEmpty());
-        return classesInRules.contains(classValue.impl());
+        return classesInRules.contains(classValue);
     }
 
     inline bool hasSelectorForId(const AtomicString& idValue) const
     {
         ASSERT(!idValue.isEmpty());
-        return idsInRules.contains(idValue.impl());
+        return idsInRules.contains(idValue);
     }
 
     HashSet<AtomicString> idsInRules;