<input type=number>: accept localized digits without showing them.

third_party/WebKit/Source/platform/text/PlatformLocale.h

 /*
  * Copyright (C) 2012 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:
  * 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
  *     notice, this list of conditions and the following disclaimer in the
@@ skipping 49 matching lines @@
   // HTML floating-point number format. The input string is provided by a end
   // user, and might not be a number string. It's ok that the function returns
   // a string which is not conforms to the HTML floating-point number format,
   // callers of this function are responsible to check the format of the
   // resultant string.
   String convertFromLocalizedNumber(const String&);
 
   // Remove characters from |input| if a character is not included in
   // locale-specific number characters and |standardChars|.
   String stripInvalidNumberCharacters(const String& input,
-                                      const String& standardChars) const;
+                                      const String& standardChars);
 
   // Returns localized decimal separator, e.g. "." for English, "," for French.
   String localizedDecimalSeparator();
 
   // Returns date format in Unicode TR35 LDML[1] containing day of month,
   // month, and year, e.g. "dd/mm/yyyy"
   // [1] LDML http://unicode.org/reports/tr35/#Date_Format_Patterns
   virtual String dateFormat() = 0;
 
   // Returns a year-month format in Unicode TR35 LDML.
@@ skipping 96 matching lines @@
   String m_positivePrefix;
   String m_positiveSuffix;
   String m_negativePrefix;
   String m_negativeSuffix;
   String m_acceptableNumberCharacters;
   bool m_hasLocaleData;
 };
 
 }  // namespace blink
 #endif