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 231 matching lines @@
         const Vector<StyleRuleFontFace*> fontFaceRules = authorRules.fontFaceRules();
         for (unsigned i = 0; i < fontFaceRules.size(); ++i)
             fontSelector()->addFontFaceRule(fontFaceRules[i]);
         if (fontFaceRules.size())
             invalidateMatchedPropertiesCache();
     } else {
         addTreeBoundaryCrossingRules(authorRules.shadowDistributedRules(), scope);
     }
 }
 
+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;
 
     treeBoundaryCrossingRules().reset(scopingNode);
 
@@ skipping 1155 matching lines @@
 bool StyleResolver::affectedByViewportChange() const
 {
     for (unsigned i = 0; i < m_viewportDependentMediaQueryResults.size(); ++i) {
         if (m_medium->eval(&m_viewportDependentMediaQueryResults[i]->m_expression) != m_viewportDependentMediaQueryResults[i]->m_result)
             return true;
     }
     return false;
 }
 
 } // namespace WebCore