rAc: make requestAutocomplete() return a promise.

Source/core/dom/DOMException.h

 /*
  * Copyright (C) 2007, 2008 Apple 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 38 matching lines @@
     String message() const { return m_sanitizedMessage; }
     String toString() const;
 
     // This is the message that's exposed to the console: if an unsanitized message is present, we prefer it.
     String messageForConsole() const { return !m_unsanitizedMessage.isEmpty() ? m_unsanitizedMessage : m_sanitizedMessage; }
     String toStringForConsole() const;
 
     static String getErrorName(ExceptionCode);
     static String getErrorMessage(ExceptionCode);
 
+protected:
+    DOMException(unsigned short m_code, const String& name, const String& sanitizedMessage = String(), const String& unsanitizedMessage = String());
+
 private:
-    DOMException(unsigned short m_code, const String& name, const String& sanitizedMessage, const String& unsanitizedMessage);
-
     unsigned short m_code;
     String m_name;
     String m_sanitizedMessage;
     String m_unsanitizedMessage;
 };
 
 } // namespace WebCore
 
 #endif // DOMException_h