Avoid WTF::Vector::at() and operator[] in core/html.

third_party/WebKit/Source/core/html/HTMLCollection.cpp

 /*
  * Copyright (C) 1999 Lars Knoll (knoll@kde.org)
  *           (C) 1999 Antti Koivisto (koivisto@kde.org)
  * Copyright (C) 2003-2008, 2011, 2012, 2014 Apple Inc. All rights reserved.
  * Copyright (C) 2014 Samsung Electronics. 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 494 matching lines @@
 void HTMLCollection::namedItems(const AtomicString& name,
                                 HeapVector<Member<Element>>& result) const {
   DCHECK(result.isEmpty());
   if (name.isEmpty())
     return;
 
   updateIdNameCache();
 
   const NamedItemCache& cache = namedItemCache();
   if (HeapVector<Member<Element>>* idResults = cache.getElementsById(name)) {
-    for (unsigned i = 0; i < idResults->size(); ++i)
-      result.append(idResults->at(i));
+    for (const auto& element : *idResults)
+      result.append(element);
   }
   if (HeapVector<Member<Element>>* nameResults =
           cache.getElementsByName(name)) {
-    for (unsigned i = 0; i < nameResults->size(); ++i)
-      result.append(nameResults->at(i));
+    for (const auto& element : *nameResults)
+      result.append(element);
   }
 }
 
 HTMLCollection::NamedItemCache::NamedItemCache() {}
 
 DEFINE_TRACE(HTMLCollection) {
   visitor->trace(m_namedItemCache);
   visitor->trace(m_collectionItemsCache);
   LiveNodeListBase::trace(visitor);
 }
 
 }  // namespace blink