Add removeAll method to sets and maps and use them

Source/core/dom/StyleEngine.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 362 matching lines @@
 
         for (TreeScopeSet::iterator it = treeScopes.begin(); it != treeScopes.end(); ++it) {
             TreeScope* treeScope = *it;
             ASSERT(treeScope != m_document);
             ShadowTreeStyleSheetCollection* collection = static_cast<ShadowTreeStyleSheetCollection*>(styleSheetCollectionFor(*treeScope));
             ASSERT(collection);
             collection->updateActiveStyleSheets(this, updateMode);
             if (!collection->hasStyleSheetCandidateNodes())
                 treeScopesRemoved.add(treeScope);
         }
-        if (!treeScopesRemoved.isEmpty())
-            for (HashSet<TreeScope*>::iterator it = treeScopesRemoved.begin(); it != treeScopesRemoved.end(); ++it)
-                m_activeTreeScopes.remove(*it);
+        m_activeTreeScopes.removeAll(treeScopesRemoved);
     }
 
     InspectorInstrumentation::activeStyleSheetsUpdated(&m_document);
     m_usesRemUnits = m_documentStyleSheetCollection.usesRemUnits();
 
     m_dirtyTreeScopes.clear();
     m_documentScopeDirty = false;
 
     return requiresFullStyleRecalc;
 }
@@ skipping 241 matching lines @@
     visitor->trace(m_authorStyleSheets);
     visitor->trace(m_documentStyleSheetCollection);
     visitor->trace(m_styleSheetCollectionMap);
     visitor->trace(m_resolver);
     visitor->trace(m_fontSelector);
     visitor->trace(m_textToSheetCache);
     visitor->trace(m_sheetToTextCache);
 }
 
 }