Checks the DomKey in the non-printable map to determine whether a key event is non-character.

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 <stddef.h>
 #include <xkbcommon/xkbcommon-names.h>
 
 #include <algorithm>
@@ skipping 734 matching lines @@
     return false;
   }
   xkb_mod_mask_t xkb_flags = EventFlagsToXkbFlags(flags);
   // Obtain keysym and character.
   xkb_keysym_t xkb_keysym;
   uint32_t character = 0;
   if (!XkbLookup(xkb_keycode, xkb_flags, &xkb_keysym, &character))
     return false;
 
   // Classify the keysym and convert to DOM and VKEY representations.
-  if ((character == 0) &&
-      ((xkb_keysym != XKB_KEY_at) || (flags & EF_CONTROL_DOWN) == 0)) {
+  if (xkb_keysym != XKB_KEY_at || (flags & EF_CONTROL_DOWN) == 0) {
     // Non-character key. (We only support NUL as ^@.)
     *dom_key = NonPrintableXKeySymToDomKey(xkb_keysym);
-    if (*dom_key == DomKey::NONE) {
+    if (*dom_key != DomKey::NONE) {
+      *key_code = NonPrintableDomKeyToKeyboardCode(*dom_key);
+      if (*key_code == VKEY_UNKNOWN)
+        *key_code = DomCodeToUsLayoutNonLocatedKeyboardCode(dom_code);
+      return true;
+    }
+    if (character == 0) {
       *dom_key = DomKey::UNIDENTIFIED;
-      *key_code = VKEY_UNKNOWN;
-    } else {
-      *key_code = NonPrintableDomKeyToKeyboardCode(*dom_key);
+      *key_code = DomCodeToUsLayoutNonLocatedKeyboardCode(dom_code);
+      return true;
     }
-    if (*key_code == VKEY_UNKNOWN)
-      *key_code = DomCodeToUsLayoutNonLocatedKeyboardCode(dom_code);
-    return true;
   }
 
   // Per UI Events rules for determining |key|, if the character is
   // non-printable and a non-shiftlike modifier is down, we preferentially
   // return a printable key as if the modifier were not down.
   // https://w3c.github.io/uievents/#keys-guidelines
   const int kNonShiftlikeModifiers =
       EF_CONTROL_DOWN | EF_ALT_DOWN | EF_COMMAND_DOWN;
   if ((flags & kNonShiftlikeModifiers) && IsControlCharacter(character)) {
     int normal_ui_flags = flags & ~kNonShiftlikeModifiers;
@@ skipping 192 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