Make sure getAttribute() / setAttribute() callers use AtomicStrings

Source/core/html/HTMLSelectElement.cpp

 /*
  * Copyright (C) 2010 Nokia Corporation and/or its subsidiary(-ies).
  * Copyright (C) 1999 Lars Knoll (knoll@kde.org)
  *           (C) 1999 Antti Koivisto (koivisto@kde.org)
  *           (C) 2001 Dirk Mueller (mueller@kde.org)
  * Copyright (C) 2004, 2005, 2006, 2007, 2009, 2010, 2011 Apple Inc. All rights reserved.
  *           (C) 2006 Alexey Proskuryakov (ap@nypop.com)
  * Copyright (C) 2010 Google Inc. All rights reserved.
  * Copyright (C) 2009 Torch Mobile Inc. All rights reserved. (http://www.torchmobile.com/)
  *
@@ skipping 372 matching lines @@
 void HTMLSelectElement::accessKeyAction(bool sendMouseEvents)
 {
     focus();
     dispatchSimulatedClick(0, sendMouseEvents ? SendMouseUpDownEvents : SendNoEvents);
 }
 
 void HTMLSelectElement::setMultiple(bool multiple)
 {
     bool oldMultiple = this->multiple();
     int oldSelectedIndex = selectedIndex();
-    setAttribute(multipleAttr, multiple ? "" : 0);
+    setAttribute(multipleAttr, multiple ? emptyAtom : nullAtom);
 
     // Restore selectedIndex after changing the multiple flag to preserve
     // selection as single-line and multi-line has different defaults.
     if (oldMultiple != this->multiple())
         setSelectedIndex(oldSelectedIndex);
 }
 
 void HTMLSelectElement::setSize(int size)
 {
     setIntegralAttribute(sizeAttr, size);
@@ skipping 1174 matching lines @@
     remove(index);
     return true;
 }
 
 bool HTMLSelectElement::isInteractiveContent() const
 {
     return true;
 }
 
 } // namespace