Use removeFontFace to avoid resetting fontSelector.

Source/core/dom/Document.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 1922 matching lines @@
 StyleResolver& Document::ensureStyleResolver() const
 {
     return m_styleEngine->ensureResolver();
 }
 
 void Document::clearStyleResolver()
 {
     m_styleEngine->clearResolver();
 }
 
+CSSFontSelector* Document::fontSelector() const
+{
+    return m_styleEngine->fontSelector();
+}
+
 void Document::attach(const AttachContext& context)
 {
     ASSERT(m_lifecyle.state() == DocumentLifecycle::Inactive);
     ASSERT(!m_axObjectCache || this != topDocument());
 
     m_renderView = new RenderView(this);
     setRenderer(m_renderView);
 
     m_renderView->setIsInWindow(true);
     m_renderView->setStyle(StyleResolver::styleForDocument(*this));
@@ skipping 3251 matching lines @@
 }
 
 FastTextAutosizer* Document::fastTextAutosizer()
 {
     if (!m_fastTextAutosizer && RuntimeEnabledFeatures::fastTextAutosizingEnabled())
         m_fastTextAutosizer = FastTextAutosizer::create(this);
     return m_fastTextAutosizer.get();
 }
 
 } // namespace WebCore