Set ui::KeyEvent::key_ (DOM Level 3 key) under X11.

ui/events/ozone/layout/xkb/xkb_keyboard_code_conversion.h

 // Copyright 2014 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #ifndef UI_EVENTS_OZONE_LAYOUT_XKB_XKB_KEYBOARD_CODE_CONVERSION_H_
 #define UI_EVENTS_OZONE_LAYOUT_XKB_XKB_KEYBOARD_CODE_CONVERSION_H_
 
 // TODO(kpschoedel): move this file out of Ozone so that it can be used to
 // determine DomKey for desktop X11, OR switch desktop X11 to use the Ozone
 // keyboard layout interface.
 
 #include <xkbcommon/xkbcommon.h>
 
 #include "base/strings/string16.h"
 #include "ui/events/keycodes/keyboard_codes.h"
 
 namespace ui {
 
 enum class DomKey;
 
-// Returns the DomKey associated with a non-character xkb_keysym_t.
-// Returns DomKey::NONE for unrecognized keysyms, which includes
-// all printable characters.
-DomKey NonPrintableXkbKeySymToDomKey(xkb_keysym_t keysym);
-
 // Returns the dead key combining character associated with an xkb_keysym_t,
 // or 0 if the keysym is not recognized.
 base::char16 DeadXkbKeySymToCombiningCharacter(xkb_keysym_t keysym);
 
 }  // namespace ui
 
 #endif  // UI_EVENTS_OZONE_LAYOUT_XKB_XKB_KEYBOARD_CODE_CONVERSION_H_