Consistently use AtomicString for namespaceURI / prefix

Source/core/xml/XPathGrammar.y

 /*
  * Copyright 2005 Frerich Raabe <raabe@kde.org>
  * Copyright (C) 2006 Apple Inc. All rights reserved.
  * Copyright (C) 2007 Alexey Proskuryakov <ap@webkit.org>
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions
  * are met:
  * 
  * 1. Redistributions of source code must retain the above copyright
@@ skipping 174 matching lines @@
             $$ = new Step(Step::ChildAxis, *$1, *$2);
             parser->deletePredicateVector($2);
         } else
             $$ = new Step(Step::ChildAxis, *$1);
         parser->deleteNodeTest($1);
         parser->registerParseNode($$);
     }
     |
     NAMETEST OptionalPredicateList
     {
-        String localName;
-        String namespaceURI;
+        AtomicString localName;
+        AtomicString namespaceURI;
         if (!parser->expandQName(*$1, localName, namespaceURI)) {
             parser->m_gotNamespaceError = true;
             YYABORT;
         }
         
         if ($2) {
             $$ = new Step(Step::ChildAxis, Step::NodeTest(Step::NodeTest::NameTest, localName, namespaceURI), *$2);
             parser->deletePredicateVector($2);
         } else
             $$ = new Step(Step::ChildAxis, Step::NodeTest(Step::NodeTest::NameTest, localName, namespaceURI));
         parser->deleteString($1);
         parser->registerParseNode($$);
     }
     |
     AxisSpecifier NodeTest OptionalPredicateList
     {
         if ($3) {
             $$ = new Step($1, *$2, *$3);
             parser->deletePredicateVector($3);
         } else
             $$ = new Step($1, *$2);
         parser->deleteNodeTest($2);
         parser->registerParseNode($$);
     }
     |
     AxisSpecifier NAMETEST OptionalPredicateList
     {
-        String localName;
-        String namespaceURI;
+        AtomicString localName;
+        AtomicString namespaceURI;
         if (!parser->expandQName(*$2, localName, namespaceURI)) {
             parser->m_gotNamespaceError = true;
             YYABORT;
         }
 
         if ($3) {
             $$ = new Step($1, Step::NodeTest(Step::NodeTest::NameTest, localName, namespaceURI), *$3);
             parser->deletePredicateVector($3);
         } else
             $$ = new Step($1, Step::NodeTest(Step::NodeTest::NameTest, localName, namespaceURI));
@@ skipping 309 matching lines @@
     MINUS UnaryExpr
     {
         $$ = new Negative;
         $$->addSubExpression(adoptPtr($2));
         parser->unregisterParseNode($2);
         parser->registerParseNode($$);
     }
     ;
 
 %%