Remove inefficiency from HTMLCollection::namedItems()

Source/core/html/HTMLCollection.cpp

 /*
  * Copyright (C) 1999 Lars Knoll (knoll@kde.org)
  *           (C) 1999 Antti Koivisto (koivisto@kde.org)
  * Copyright (C) 2003, 2004, 2005, 2006, 2007, 2008, 2011, 2012 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 489 matching lines @@
 
 void HTMLCollection::namedItems(const AtomicString& name, WillBeHeapVector<RefPtrWillBeMember<Element> >& result) const
 {
     ASSERT(result.isEmpty());
     if (name.isEmpty())
         return;
 
     updateIdNameCache();
 
     const NamedItemCache& cache = namedItemCache();
-    WillBeHeapVector<RawPtrWillBeMember<Element> >* idResults = cache.getElementsById(name);
-    WillBeHeapVector<RawPtrWillBeMember<Element> >* nameResults = cache.getElementsByName(name);
-
-    for (unsigned i = 0; idResults && i < idResults->size(); ++i)
-        result.append(idResults->at(i));
-
-    for (unsigned i = 0; nameResults && i < nameResults->size(); ++i)
-        result.append(nameResults->at(i));
+    if (WillBeHeapVector<RawPtrWillBeMember<Element> >* idResults = cache.getElementsById(name)) {
+        for (unsigned i = 0; i < idResults->size(); ++i)
+            result.append(idResults->at(i));
+    }
+    if (WillBeHeapVector<RawPtrWillBeMember<Element> >* nameResults = cache.getElementsByName(name)) {
+        for (unsigned i = 0; i < nameResults->size(); ++i)
+            result.append(nameResults->at(i));
+    }
 }
 
 HTMLCollection::NamedItemCache::NamedItemCache()
 {
 }
 
 void HTMLCollection::trace(Visitor* visitor)
 {
     visitor->trace(m_namedItemCache);
     visitor->trace(m_collectionIndexCache);
     LiveNodeListBase::trace(visitor);
 }
 
 } // namespace WebCore