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

Source/core/page/EventHandler.cpp

 /*
  * Copyright (C) 2006, 2007, 2008, 2009, 2010, 2011 Apple Inc. All rights reserved.
  * Copyright (C) 2006 Alexey Proskuryakov (ap@webkit.org)
  * Copyright (C) 2012 Digia Plc. and/or its subsidiary(-ies)
  *
  * 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
  *    notice, this list of conditions and the following disclaimer.
@@ skipping 1758 matching lines @@
 
     frame = toHTMLFrameElementBase(target)->contentFrame();
     return true;
 }
 
 static bool findDropZone(Node* target, Clipboard* clipboard)
 {
     Element* element = target->isElementNode() ? toElement(target) : target->parentElement();
     for (; element; element = element->parentElement()) {
         bool matched = false;
-        String dropZoneStr = element->fastGetAttribute(webkitdropzoneAttr);
+        AtomicString dropZoneStr = element->fastGetAttribute(webkitdropzoneAttr);
 
         if (dropZoneStr.isEmpty())
             continue;
 
         dropZoneStr = dropZoneStr.lower();
 
         SpaceSplitString keywords(dropZoneStr, false);
         if (keywords.isNull())
             continue;
 
@@ skipping 2183 matching lines @@
 unsigned EventHandler::accessKeyModifiers()
 {
 #if OS(MACOSX)
     return PlatformEvent::CtrlKey | PlatformEvent::AltKey;
 #else
     return PlatformEvent::AltKey;
 #endif
 }
 
 } // namespace WebCore