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

Source/core/html/forms/HiddenInputType.cpp

 /*
  * Copyright (C) 2010 Google Inc. All rights reserved.
  * Copyright (C) 2011 Apple Inc. All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions are
  * met:
  *
  *     * Redistributions of source code must retain the above copyright
  * notice, this list of conditions and the following disclaimer.
@@ skipping 46 matching lines @@
 {
     // valueAttributeWasUpdatedAfterParsing() never be true for form
     // controls create by createElement() or cloneNode(). It's ok for
     // now because we restore values only to form controls created by
     // parsing.
     return element().valueAttributeWasUpdatedAfterParsing() ? FormControlState(element().value()) : FormControlState();
 }
 
 void HiddenInputType::restoreFormControlState(const FormControlState& state)
 {
-    element().setAttribute(valueAttr, state[0]);
+    element().setAttribute(valueAttr, AtomicString(state[0]));
 }
 
 bool HiddenInputType::supportsValidation() const
 {
     return false;
 }
 
 RenderObject* HiddenInputType::createRenderer(RenderStyle*) const
 {
     ASSERT_NOT_REACHED();
     return 0;
 }
 
 void HiddenInputType::accessKeyAction(bool)
 {
 }
 
 bool HiddenInputType::rendererIsNeeded()
 {
     return false;
 }
 
 bool HiddenInputType::storesValueSeparateFromAttribute()
 {
     return false;
 }
 
 void HiddenInputType::setValue(const String& sanitizedValue, bool, TextFieldEventBehavior)
 {
-    element().setAttribute(valueAttr, sanitizedValue);
+    element().setAttribute(valueAttr, AtomicString(sanitizedValue));
 }
 
 bool HiddenInputType::isHiddenType() const
 {
     return true;
 }
 
 bool HiddenInputType::appendFormData(FormDataList& encoding, bool isMultipartForm) const
 {
     if (equalIgnoringCase(element().name(), "_charset_")) {
         encoding.appendData(element().name(), String(encoding.encoding().name()));
         return true;
     }
     return InputType::appendFormData(encoding, isMultipartForm);
 }
 
 bool HiddenInputType::shouldRespectHeightAndWidthAttributes()
 {
     return true;
 }
 
 } // namespace WebCore