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

Source/core/html/HTMLImageElement.cpp

 /*
  * Copyright (C) 1999 Lars Knoll (knoll@kde.org)
  *           (C) 1999 Antti Koivisto (koivisto@kde.org)
  * Copyright (C) 2004, 2005, 2006, 2007, 2008, 2010 Apple Inc. All rights reserved.
  * Copyright (C) 2010 Google Inc. All rights reserved.
  *
  * This library is free software; you can redistribute it and/or
  * modify it under the terms of the GNU Library General Public
  * License as published by the Free Software Foundation; either
  * version 2 of the License, or (at your option) any later version.
@@ skipping 126 matching lines @@
         setAttributeEventListener(EventTypeNames::beforeload, createAttributeEventListener(this, name, value));
     else if (name == compositeAttr) {
         // FIXME: images don't support blend modes in their compositing attribute.
         blink::WebBlendMode blendOp = blink::WebBlendModeNormal;
         if (!parseCompositeAndBlendOperator(value, m_compositeOperator, blendOp))
             m_compositeOperator = CompositeSourceOver;
     } else
         HTMLElement::parseAttribute(name, value);
 }
 
-String HTMLImageElement::altText() const
+const AtomicString& HTMLImageElement::altText() const
 {
     // lets figure out the alt text.. magic stuff
     // http://www.w3.org/TR/1998/REC-html40-19980424/appendix/notes.html#altgen
     // also heavily discussed by Hixie on bugzilla
-    String alt = getAttribute(altAttr);
+    if (!getAttribute(altAttr).isNull())
+        return getAttribute(altAttr);
     // fall back to title attribute
-    if (alt.isNull())
-        alt = getAttribute(titleAttr);
-    return alt;
+    return getAttribute(titleAttr);
 }
 
 RenderObject* HTMLImageElement::createRenderer(RenderStyle* style)
 {
     if (style->hasContent())
         return RenderObject::createObject(this, style);
 
     RenderImage* image = new RenderImage(this);
     image->setImageResource(RenderImageResource::create());
     image->setImageDevicePixelRatio(m_imageDevicePixelRatio);
@@ skipping 145 matching lines @@
     setIntegralAttribute(heightAttr, value);
 }
 
 KURL HTMLImageElement::src() const
 {
     return document().completeURL(getAttribute(srcAttr));
 }
 
 void HTMLImageElement::setSrc(const String& value)
 {
-    setAttribute(srcAttr, value);
+    setAttribute(srcAttr, AtomicString(value));
 }
 
 void HTMLImageElement::setWidth(int value)
 {
     setIntegralAttribute(widthAttr, value);
 }
 
 int HTMLImageElement::x() const
 {
     RenderObject* r = renderer();
@@ skipping 57 matching lines @@
 
     return m_imageLoader.image()->image();
 }
 
 bool HTMLImageElement::isInteractiveContent() const
 {
     return fastHasAttribute(usemapAttr);
 }
 
 }