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

Source/core/css/resolver/StyleResolver.h

 /*
  * Copyright (C) 1999 Lars Knoll (knoll@kde.org)
  * Copyright (C) 2003, 2004, 2005, 2006, 2007, 2008, 2009, 2010, 2011 Apple Inc. 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.
  *
  * This library is distributed in the hope that it will be useful,
@@ skipping 124 matching lines @@
     // FIXME: This only has 5 callers and should be removed. Callers should be explicit about
     // their dependency on Document* instead of grabbing one through StyleResolver.
     Document& document() { return m_document; }
 
     // FIXME: It could be better to call appendAuthorStyleSheets() directly after we factor StyleResolver further.
     // https://bugs.webkit.org/show_bug.cgi?id=108890
     void appendAuthorStyleSheets(unsigned firstNew, const Vector<RefPtr<CSSStyleSheet> >&);
     void resetAuthorStyle(const ContainerNode*);
     void resetAtHostRules(const ShadowRoot*);
     void finishAppendAuthorStyleSheets();
+    void resetFontSelector();
 
     TreeBoundaryCrossingRules& treeBoundaryCrossingRules() { return m_treeBoundaryCrossingRules; }
     void processScopedRules(const RuleSet& authorRules, const KURL&, ContainerNode* scope = 0);
 
     SelectorFilter& selectorFilter() { return m_selectorFilter; }
 
     void setBuildScopedStyleTreeInDocumentOrder(bool enabled) { m_styleTree.setBuildInDocumentOrder(enabled); }
     bool buildScopedStyleTreeInDocumentOrder() const { return m_styleTree.buildInDocumentOrder(); }
     bool styleTreeHasOnlyScopedResolverForDocument() const { return m_styleTree.hasOnlyScopedResolverForDocument(); }
     ScopedStyleResolver* styleTreeScopedStyleResolverForDocument() const { return m_styleTree.scopedStyleResolverForDocument(); }
@@ skipping 168 matching lines @@
         PseudoId ignoreDynamicPseudo = NOPSEUDO;
         if (selectorChecker.match(selectorCheckingContext, ignoreDynamicPseudo, DOMSiblingTraversalStrategy()) == SelectorChecker::SelectorMatches)
             return true;
     }
     return false;
 }
 
 } // namespace WebCore
 
 #endif // StyleResolver_h