Clear baseLayoutStyle when the font selector version has increased.

Source/platform/fonts/Font.cpp

 /*
  * Copyright (C) 1999 Lars Knoll (knoll@kde.org)
  *           (C) 1999 Antti Koivisto (koivisto@kde.org)
  *           (C) 2000 Dirk Mueller (mueller@kde.org)
  * Copyright (C) 2003, 2006, 2010, 2011 Apple Inc. All rights reserved.
  * Copyright (c) 2007, 2008, 2010 Google 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
@@ skipping 924 matching lines @@
             } else {
                 if (delta <= 0)
                     break;
             }
         }
     }
 
     return offset;
 }
 
+bool Font::loadingCustomFonts() const
+{
+    return m_fontFallbackList && m_fontFallbackList->loadingCustomFonts();
+}
+
+bool Font::isFallbackValid() const
+{
+    return !m_fontFallbackList || m_fontFallbackList->isValid();
+}
+
 } // namespace blink