Use removeFontFace to avoid resetting fontSelector.

Source/platform/fonts/GenericFontFamilySettings.h

 /*
  * Copyright (C) 2013 Google 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:
  *
  *     * Redistributions of source code must retain the above copyright
  * notice, this list of conditions and the following disclaimer.
  *     * Redistributions in binary form must reproduce the above
@@ skipping 55 matching lines @@
 
     void setFantasy(const AtomicString&, UScriptCode = USCRIPT_COMMON);
     const AtomicString& fantasy(UScriptCode = USCRIPT_COMMON) const;
 
     void setPictograph(const AtomicString&, UScriptCode = USCRIPT_COMMON);
     const AtomicString& pictograph(UScriptCode = USCRIPT_COMMON) const;
 
     // Only called by InternalSettings to clear font family maps.
     void reset();
 
+    GenericFontFamilySettings& operator=(const GenericFontFamilySettings&);
+
 private:
-    GenericFontFamilySettings& operator=(const GenericFontFamilySettings&) WTF_DELETED_FUNCTION;
-
     // UScriptCode uses -1 and 0 for UScriptInvalidCode and UScriptCommon.
     // We need to use -2 and -3 for empty value and deleted value.
     struct UScriptCodeHashTraits : WTF::GenericHashTraits<int> {
         static const bool emptyValueIsZero = false;
         static int emptyValue() { return -2; }
         static void constructDeletedValue(int& slot) { slot = -3; }
         static bool isDeletedValue(int value) { return value == -3; }
     };
 
     typedef HashMap<int, AtomicString, DefaultHash<int>::Hash, UScriptCodeHashTraits> ScriptFontFamilyMap;
 
     void setGenericFontFamilyMap(ScriptFontFamilyMap&, const AtomicString&, UScriptCode);
     const AtomicString& genericFontFamilyForScript(const ScriptFontFamilyMap&, UScriptCode) const;
 
     ScriptFontFamilyMap m_standardFontFamilyMap;
     ScriptFontFamilyMap m_serifFontFamilyMap;
     ScriptFontFamilyMap m_fixedFontFamilyMap;
     ScriptFontFamilyMap m_sansSerifFontFamilyMap;
     ScriptFontFamilyMap m_cursiveFontFamilyMap;
     ScriptFontFamilyMap m_fantasyFontFamilyMap;
     ScriptFontFamilyMap m_pictographFontFamilyMap;
 };
 
 }
 
 #endif