Minimize performance regression caused by r157508

Source/core/dom/Element.cpp

 /*
  * Copyright (C) 1999 Lars Knoll (knoll@kde.org)
  *           (C) 1999 Antti Koivisto (koivisto@kde.org)
  *           (C) 2001 Peter Kelly (pmk@post.com)
  *           (C) 2001 Dirk Mueller (mueller@kde.org)
  *           (C) 2007 David Smith (catfish.man@gmail.com)
  * Copyright (C) 2004, 2005, 2006, 2007, 2008, 2009, 2010, 2012, 2013 Apple Inc. All rights reserved.
  *           (C) 2007 Eric Seidel (eric@webkit.org)
  *
  * This library is free software; you can redistribute it and/or
@@ skipping 160 matching lines @@
 }
 
 static void removeAttrNodeListForElement(Element* element)
 {
     ASSERT(element->hasSyntheticAttrChildNodes());
     ASSERT(attrNodeListMap().contains(element));
     attrNodeListMap().remove(element);
     element->setHasSyntheticAttrChildNodes(false);
 }
 
-static Attr* findAttrNodeInList(AttrNodeList& attrNodeList, const QualifiedName& name)
+static Attr* findAttrNodeInList(const AttrNodeList& attrNodeList, const QualifiedName& name)
 {
-    for (unsigned i = 0; i < attrNodeList.size(); ++i) {
-        if (attrNodeList[i]->qualifiedName() == name)
-            return attrNodeList[i].get();
+    AttrNodeList::const_iterator end = attrNodeList.end();
+    for (AttrNodeList::const_iterator it = attrNodeList.begin(); it != end; ++it) {
+        if ((*it)->qualifiedName() == name)

[eseidel, 2013/11/06 03:12:24]

I wonder if this really wants matches() :)  Which doesn't respect prefix. 
Depends on what the callers are looking for.  This is a very common issue which
only is visibile in XML documents (where prefixes exist).  Eventually perhaps
we'll remove main-document-XML from the web and all these bugs will go away.

+            return it->get();
     }
     return 0;
 }
 
 PassRefPtr<Element> Element::create(const QualifiedName& tagName, Document* document)
 {
     return adoptRef(new Element(tagName, document, CreateElement));
 }
 
 Element::~Element()
@@ skipping 720 matching lines @@
         if (index != kNotFound)
             removeAttributeInternal(index, inSynchronizationOfLazyAttribute);
         return;
     }
 
     if (index == kNotFound) {
         addAttributeInternal(name, newValue, inSynchronizationOfLazyAttribute);
         return;
     }
 
-    QualifiedName existingAttributeName = attributeItem(index)->name();
+    const Attribute* existingAttribute = attributeItem(index);
+    QualifiedName existingAttributeName = existingAttribute->name();
 
     if (!inSynchronizationOfLazyAttribute)
-        willModifyAttribute(existingAttributeName, attributeItem(index)->value(), newValue);
+        willModifyAttribute(existingAttributeName, existingAttribute->value(), newValue);
 
-    if (newValue != attributeItem(index)->value()) {
+    if (newValue != existingAttribute->value()) {
         // If there is an Attr node hooked to this attribute, the Attr::setValue() call below
         // will write into the ElementData.
         // FIXME: Refactor this so it makes some sense.
         if (RefPtr<Attr> attrNode = inSynchronizationOfLazyAttribute ? 0 : attrIfExists(existingAttributeName))
             attrNode->setValue(newValue);
         else
             ensureUniqueElementData()->attributeItem(index)->setValue(newValue);
     }
 
     if (!inSynchronizationOfLazyAttribute)
@@ skipping 2534 matching lines @@
     // Before doing so, we need to resolve issues in HTMLSelectElement::recalcListItems
     // and RenderMenuList::setText. See also https://bugs.webkit.org/show_bug.cgi?id=88405
     if (hasTagName(optionTag) || hasTagName(optgroupTag))
         return false;
     if (FullscreenElementStack::isActiveFullScreenElement(this))
         return false;
     return true;
 }
 
 } // namespace WebCore