fontSelector should be reset when removing stylesheets which has @font-face rule.

Source/core/css/resolver/StyleResolver.cpp

 /*
  * Copyright (C) 1999 Lars Knoll (knoll@kde.org)
  *           (C) 2004-2005 Allan Sandfeld Jensen (kde@carewolf.com)
  * Copyright (C) 2006, 2007 Nicholas Shanks (webkit@nickshanks.com)
  * Copyright (C) 2005, 2006, 2007, 2008, 2009, 2010, 2011, 2012, 2013 Apple Inc. All rights reserved.
  * Copyright (C) 2007 Alexey Proskuryakov <ap@webkit.org>
  * Copyright (C) 2007, 2008 Eric Seidel <eric@webkit.org>
  * Copyright (C) 2008, 2009 Torch Mobile Inc. All rights reserved. (http://www.torchmobile.com/)
  * Copyright (c) 2011, Code Aurora Forum. All rights reserved.
  * Copyright (C) Research In Motion Limited 2011. All rights reserved.
@@ skipping 204 matching lines @@
 void StyleResolver::finishAppendAuthorStyleSheets()
 {
     collectFeatures();
 
     if (document().renderer() && document().renderer()->style())
         document().renderer()->style()->font().update(fontSelector());
 
     collectViewportRules();
 }
 
+void StyleResolver::resetFontSelector()
+{
+    ASSERT(m_fontSelector);
+    m_fontSelector->unregisterForInvalidationCallbacks(this);
+    m_fontSelector->clearDocument();
+    invalidateMatchedPropertiesCache();
+
+    m_fontSelector = CSSFontSelector::create(&m_document);
+    m_fontSelector->registerForInvalidationCallbacks(this);
+}
+
 void StyleResolver::resetAuthorStyle(const ContainerNode* scopingNode)
 {
     // FIXME: When chanking scoped attribute, scopingNode's hasScopedHTMLStyleChild has been already modified.
     // So we cannot use hasScopedHTMLStyleChild flag here.
     ScopedStyleResolver* resolver = scopingNode ? m_styleTree.lookupScopedStyleResolverFor(scopingNode) : m_styleTree.scopedStyleResolverForDocument();
     if (!resolver)
         return;
 
     m_ruleSets.treeBoundaryCrossingRules().reset(scopingNode);
 
@@ skipping 1365 matching lines @@
         m_matchedPropertiesSearches, m_matchedPropertiesHit, m_matchedPropertiesSharedInheritedHit, m_matchedPropertiesToCache, m_matchedPropertiesEnteredIntoCache);
 
     fprintf(stderr, "Total:\n");
     printStyleStats(m_totalSearches, m_totalElementsEligibleForSharing, m_totalStylesShared, m_totalSearchFoundSiblingForSharing, m_totalSearchesMissedSharing,
         m_totalMatchedPropertiesSearches, m_totalMatchedPropertiesHit, m_totalMatchedPropertiesSharedInheritedHit, m_totalMatchedPropertiesToCache, m_totalMatchedPropertiesEnteredIntoCache);
     fprintf(stderr, "--------------------------------------------------------------------------------\n");
 }
 #endif
 
 } // namespace WebCore