Clear baseLayoutStyle when the font selector version has increased.

Source/platform/fonts/FontFallbackList.cpp

 /*
  * Copyright (C) 2006 Apple Computer, Inc.  All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions
  * are met:
  *
  * 1.  Redistributions of source code must retain the above copyright
  *     notice, this list of conditions and the following disclaimer.
  * 2.  Redistributions in binary form must reproduce the above copyright
@@ skipping 226 matching lines @@
     ASSERT(FontCache::fontCache()->generation() == m_generation);
     RefPtr<FontData> result = getFontData(fontDescription, m_familyIndex);
     if (result) {
         m_fontList.append(result);
         if (result->isLoadingFallback())
             m_hasLoadingFallback = true;
     }
     return result.get();
 }
 
+bool FontFallbackList::isValid() const
+{
+    if (!m_fontSelector)
+        return m_fontSelectorVersion == 0;
+
+    return m_fontSelector->version() == m_fontSelectorVersion;
+}
+
 } // namespace blink