Revise Control+key restriction for XKB layouts.

ui/events/ozone/layout/xkb/xkb_keyboard_layout_engine.cc

 // 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.
 
 #include "ui/events/ozone/layout/xkb/xkb_keyboard_layout_engine.h"
 
 #include <xkbcommon/xkbcommon-names.h>
 
 #include "base/bind.h"
 #include "base/location.h"
@@ skipping 757 matching lines @@
   *dom_key = NonPrintableXkbKeySymToDomKey(xkb_keysym);
   if (*dom_key == DomKey::NONE) {
     *dom_key = CharacterToDomKey(*character);
     *key_code = AlphanumericKeyboardCode(*character);
     if (*key_code == VKEY_UNKNOWN) {
       *key_code = DifficultKeyboardCode(dom_code, flags, xkb_keycode, xkb_flags,
                                         xkb_keysym, *dom_key, *character);
       if (*key_code == VKEY_UNKNOWN)
         *key_code = DomCodeToUsLayoutKeyboardCode(dom_code);
     }
-
-    if ((flags & EF_CONTROL_DOWN) == EF_CONTROL_DOWN) {
-      // Use GetCharacterFromKeyCode() to set |character| to 0x0 for keys that
-      // are not part of the accepted set of Control+Key combinations.
-      *character = GetCharacterFromKeyCode(*key_code, flags);
-    }
+    // If the Control key is down, only allow ASCII control characters to be
+    // returned, regardless of the key layout. crbug.com/450849
+    if ((flags & EF_CONTROL_DOWN) && (*character >= 0x20))
+      *character = 0;
   } else if (*dom_key == DomKey::DEAD) {
     *character = DeadXkbKeySymToCombiningCharacter(xkb_keysym);
     *key_code = DomCodeToUsLayoutKeyboardCode(dom_code);
   } else {
     *key_code = NonPrintableDomKeyToKeyboardCode(*dom_key);
     if (*key_code == VKEY_UNKNOWN)
       *key_code = DomCodeToUsLayoutKeyboardCode(dom_code);
   }
   return true;
 }
@@ skipping 163 matching lines @@
       close_index = layout_name.size();
     *layout_variant = layout_name.substr(parentheses_index + 1,
                                          close_index - parentheses_index - 1);
   } else if (dash_index != std::string::npos) {
     *layout_id = layout_name.substr(0, dash_index);
     *layout_variant = layout_name.substr(dash_index + 1);
   }
 }
 
 }  // namespace ui