Remove unwanted copyToVector() uses.

third_party/WebKit/Source/core/dom/Document.cpp

 /*
  * Copyright (C) 1999 Lars Knoll (knoll@kde.org)
  *           (C) 1999 Antti Koivisto (koivisto@kde.org)
  *           (C) 2001 Dirk Mueller (mueller@kde.org)
  *           (C) 2006 Alexey Proskuryakov (ap@webkit.org)
  * Copyright (C) 2004, 2005, 2006, 2007, 2008, 2009, 2011, 2012 Apple Inc. All rights reserved.
  * Copyright (C) 2008, 2009 Torch Mobile Inc. All rights reserved. (http://www.torchmobile.com/)
  * Copyright (C) 2008, 2009, 2011, 2012 Google Inc. All rights reserved.
  * Copyright (C) 2010 Nokia Corporation and/or its subsidiary(-ies)
  * Copyright (C) Research In Motion Limited 2010-2011. All rights reserved.
@@ skipping 2098 matching lines @@
     m_useElementsNeedingUpdate.remove(&element);
 }
 
 void Document::updateUseShadowTreesIfNeeded()
 {
     ScriptForbiddenScope forbidScript;
 
     if (m_useElementsNeedingUpdate.isEmpty())
         return;
 
-    HeapVector<Member<SVGUseElement>> elements;
-    copyToVector(m_useElementsNeedingUpdate, elements);
-    m_useElementsNeedingUpdate.clear();
-
+    HeapHashSet<Member<SVGUseElement>> elements;
+    m_useElementsNeedingUpdate.swap(elements);
     for (SVGUseElement* element : elements)
         element->buildPendingResource();
 }
 
 StyleResolver* Document::styleResolver() const
 {
     return m_styleEngine->resolver();
 }
 
 StyleResolver& Document::ensureStyleResolver() const
@@ skipping 3882 matching lines @@
 #ifndef NDEBUG
 using namespace blink;
 void showLiveDocumentInstances()
 {
     Document::WeakDocumentSet& set = Document::liveDocumentSet();
     fprintf(stderr, "There are %u documents currently alive:\n", set.size());
     for (Document* document : set)
         fprintf(stderr, "- Document %p URL: %s\n", document, document->url().getString().utf8().data());
 }
 #endif