[import] support document.stylesheets in imported documents.

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 335 matching lines @@
     m_documentStyleSheetCollection.clearMediaQueryRuleSetStyleSheets();
     clearMediaQueryRuleSetOnTreeScopeStyleSheets(m_activeTreeScopes);
     clearMediaQueryRuleSetOnTreeScopeStyleSheets(m_dirtyTreeScopes);
 }
 
 void StyleEngine::collectDocumentStyleSheets(DocumentStyleSheetCollector& collector)
 {
     m_documentStyleSheetCollection.collectStyleSheets(this, collector);
 }
 
+void StyleEngine::setStyleSheetsForStyleSheetList(const Vector<RefPtr<StyleSheet> >& sheets)
+{
+    m_documentStyleSheetCollection.setSheetsForSheetList(sheets);
+}
+
 bool StyleEngine::updateActiveStyleSheets(StyleResolverUpdateMode updateMode)
 {
     ASSERT(isMaster());
     ASSERT(!m_document.inStyleRecalc());
 
     if (!m_document.isActive())
         return false;
 
     bool requiresFullStyleRecalc = false;
     if (m_documentScopeDirty || updateMode == FullStyleUpdate)
@@ skipping 242 matching lines @@
 {
     HashMap<StyleSheetContents*, AtomicString>::iterator it = sheetToTextCache().find(contents);
     if (it == sheetToTextCache().end())
         return;
 
     textToSheetCache().remove(it->value);
     sheetToTextCache().remove(contents);
 }
 
 }