Use fastGetAttribute in more places

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 164 matching lines @@
             m_compositeOperator = CompositeSourceOver;
     } else
         HTMLElement::parseAttribute(name, value);
 }
 
 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
-    if (!getAttribute(altAttr).isNull())
-        return getAttribute(altAttr);
+    const AtomicString& alt = fastGetAttribute(altAttr);
+    if (!alt.isNull())
+        return alt;
     // fall back to title attribute
-    return getAttribute(titleAttr);
+    return fastGetAttribute(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 114 matching lines @@
 {
     return attribute.name() == srcAttr
         || attribute.name() == lowsrcAttr
         || attribute.name() == longdescAttr
         || (attribute.name() == usemapAttr && attribute.value().string()[0] != '#')
         || HTMLElement::isURLAttribute(attribute);
 }
 
 const AtomicString& HTMLImageElement::alt() const
 {
-    return getAttribute(altAttr);
+    return fastGetAttribute(altAttr);
 }
 
 bool HTMLImageElement::draggable() const
 {
     // Image elements are draggable by default.
     return !equalIgnoringCase(getAttribute(draggableAttr), "false");
 }
 
 void HTMLImageElement::setHeight(int value)
 {
@@ skipping 69 matching lines @@
 
     return m_imageLoader.image()->image();
 }
 
 bool HTMLImageElement::isInteractiveContent() const
 {
     return fastHasAttribute(usemapAttr);
 }
 
 }