Revise ui::DomKey to unify character and non-character codes.

DomKey becomes a single integer value corresponding to the DOM
UI Events KeyboardEvent.key string; it can represent either a
Unicode code point or one of the defined non-printable values from
<https://w3c.github.io/DOM-Level-3-Events-key/>.

In the previous representation, ui::DomKey enumerated only the non-
printable values and had a sentinel to indicated that a character value
was held separately. Much of this CL therefore merely replaces
|key, character| pairs with a single |key| value. The most substantial
changes are to
  ui/events/keycodes/dom/dom_key.h
  ui/events/keycodes/dom/keycode_converter.h
  ui/events/event.h
and associated implementations.

BUG=227231

Review URL: https://codereview.chromium.org/1284433002

Cr-Commit-Position: refs/heads/master@{#346152}

14 files changed, 28 insertions, 162 deletions

diff --git a/ui/events/ozone/BUILD.gn b/ui/events/ozone/BUILD.gn
index ce41de9..4bb3ad2 100644
--- a/ui/events/ozone/BUILD.gn
+++ b/ui/events/ozone/BUILD.gn
@@ -194,8 +194,6 @@ component("events_ozone_layout") {
       "layout/xkb/xkb_evdev_codes.cc",
       "layout/xkb/xkb_evdev_codes.h",
       "layout/xkb/xkb_key_code_converter.h",
-      "layout/xkb/xkb_keyboard_code_conversion.cc",
-      "layout/xkb/xkb_keyboard_code_conversion.h",
       "layout/xkb/xkb_keyboard_layout_engine.cc",
       "layout/xkb/xkb_keyboard_layout_engine.h",
       "layout/xkb/xkb_keysym.h",
diff --git a/ui/events/ozone/evdev/keyboard_evdev.cc b/ui/events/ozone/evdev/keyboard_evdev.cc
index 58be1c5..95a726d 100644
--- a/ui/events/ozone/evdev/keyboard_evdev.cc
+++ b/ui/events/ozone/evdev/keyboard_evdev.cc
@@ -212,9 +212,8 @@ void KeyboardEvdev::DispatchKey(unsigned int key,
   int flags = modifiers_->GetModifierFlags();
   DomKey dom_key;
   KeyboardCode key_code;
-  uint16 character;
   uint32 platform_keycode = 0;
-  if (!keyboard_layout_engine_->Lookup(dom_code, flags, &dom_key, &character,
+  if (!keyboard_layout_engine_->Lookup(dom_code, flags, &dom_key,
                                        &key_code, &platform_keycode)) {
     return;
   }
@@ -224,7 +223,7 @@ void KeyboardEvdev::DispatchKey(unsigned int key,
   }
 
   KeyEvent event(down ? ET_KEY_PRESSED : ET_KEY_RELEASED, key_code, dom_code,
-                 modifiers_->GetModifierFlags(), dom_key, character, timestamp);
+                 modifiers_->GetModifierFlags(), dom_key, timestamp);
   event.set_source_device_id(device_id);
   if (platform_keycode)
     event.set_platform_keycode(platform_keycode);
diff --git a/ui/events/ozone/events_ozone.gyp b/ui/events/ozone/events_ozone.gyp
index 37a3923..3562651 100644
--- a/ui/events/ozone/events_ozone.gyp
+++ b/ui/events/ozone/events_ozone.gyp
@@ -193,8 +193,6 @@
           'layout/xkb/xkb_evdev_codes.cc',
           'layout/xkb/xkb_evdev_codes.h',
           'layout/xkb/xkb_key_code_converter.h',
-          'layout/xkb/xkb_keyboard_code_conversion.cc',
-          'layout/xkb/xkb_keyboard_code_conversion.h',
           'layout/xkb/xkb_keyboard_layout_engine.cc',
           'layout/xkb/xkb_keyboard_layout_engine.h',
           'layout/xkb/xkb_keysym.h',
diff --git a/ui/events/ozone/layout/keyboard_layout_engine.h b/ui/events/ozone/layout/keyboard_layout_engine.h
index c4a96d4..1e15dfa 100644
--- a/ui/events/ozone/layout/keyboard_layout_engine.h
+++ b/ui/events/ozone/layout/keyboard_layout_engine.h
@@ -8,13 +8,13 @@
 #include <string>
 
 #include "base/strings/string16.h"
+#include "ui/events/keycodes/dom/dom_key.h"
 #include "ui/events/keycodes/keyboard_codes.h"
 #include "ui/events/ozone/layout/events_ozone_layout_export.h"
 
 namespace ui {
 
 enum class DomCode;
-enum class DomKey;
 
 // A KeyboardLayoutEngine provides a platform-independent interface to
 // key mapping. Key mapping provides a meaning (DomKey and character,
@@ -66,7 +66,6 @@ class EVENTS_OZONE_LAYOUT_EXPORT KeyboardLayoutEngine {
   virtual bool Lookup(DomCode dom_code,
                       int event_flags,
                       DomKey* dom_key,
-                      base::char16* character,
                       KeyboardCode* key_code,
                       uint32* platform_keycode) const = 0;
 };
diff --git a/ui/events/ozone/layout/layout_util.h b/ui/events/ozone/layout/layout_util.h
index 84d9d1d..5a2ba52 100644
--- a/ui/events/ozone/layout/layout_util.h
+++ b/ui/events/ozone/layout/layout_util.h
@@ -8,13 +8,12 @@
 // TODO(kpschoedel): consider moving this out of Ozone.
 
 #include "base/strings/string16.h"
+#include "ui/events/keycodes/dom/dom_key.h"
 #include "ui/events/keycodes/keyboard_codes.h"
 #include "ui/events/ozone/layout/events_ozone_layout_export.h"
 
 namespace ui {
 
-enum class DomKey;
-
 // Returns the ui::EventFlags value associated with a modifier key,
 // or 0 (EF_NONE) if the key is not a modifier.
 EVENTS_OZONE_LAYOUT_EXPORT int ModifierDomKeyToEventFlag(DomKey key);
diff --git a/ui/events/ozone/layout/no/no_keyboard_layout_engine.cc b/ui/events/ozone/layout/no/no_keyboard_layout_engine.cc
index 74721a1..aad89ad 100644
--- a/ui/events/ozone/layout/no/no_keyboard_layout_engine.cc
+++ b/ui/events/ozone/layout/no/no_keyboard_layout_engine.cc
@@ -26,7 +26,6 @@ bool NoKeyboardLayoutEngine::UsesAltGr() const {
 bool NoKeyboardLayoutEngine::Lookup(DomCode dom_code,
                                     int flags,
                                     DomKey* dom_key,
-                                    base::char16* character,
                                     KeyboardCode* key_code,
                                     uint32* platform_keycode) const {
   return false;
diff --git a/ui/events/ozone/layout/no/no_keyboard_layout_engine.h b/ui/events/ozone/layout/no/no_keyboard_layout_engine.h
index 00cbda9..8b6a627 100644
--- a/ui/events/ozone/layout/no/no_keyboard_layout_engine.h
+++ b/ui/events/ozone/layout/no/no_keyboard_layout_engine.h
@@ -24,7 +24,6 @@ class EVENTS_OZONE_LAYOUT_EXPORT NoKeyboardLayoutEngine
   bool Lookup(DomCode dom_code,
               int flags,
               DomKey* dom_key,
-              base::char16* character,
               KeyboardCode* key_code,
               uint32* platform_keycode) const override;
 };
diff --git a/ui/events/ozone/layout/stub/stub_keyboard_layout_engine.cc b/ui/events/ozone/layout/stub/stub_keyboard_layout_engine.cc
index 83310a7..a1e898b 100644
--- a/ui/events/ozone/layout/stub/stub_keyboard_layout_engine.cc
+++ b/ui/events/ozone/layout/stub/stub_keyboard_layout_engine.cc
@@ -41,11 +41,9 @@ bool StubKeyboardLayoutEngine::UsesAltGr() const {
 bool StubKeyboardLayoutEngine::Lookup(DomCode dom_code,
                                       int flags,
                                       DomKey* out_dom_key,
-                                      base::char16* out_character,
                                       KeyboardCode* out_key_code,
                                       uint32* platform_keycode) const {
-  return DomCodeToUsLayoutMeaning(dom_code, flags, out_dom_key, out_character,
-                                  out_key_code);
+  return DomCodeToUsLayoutDomKey(dom_code, flags, out_dom_key, out_key_code);
 }
 
 }  // namespace ui
diff --git a/ui/events/ozone/layout/stub/stub_keyboard_layout_engine.h b/ui/events/ozone/layout/stub/stub_keyboard_layout_engine.h
index a2d4912..0aa532f 100644
--- a/ui/events/ozone/layout/stub/stub_keyboard_layout_engine.h
+++ b/ui/events/ozone/layout/stub/stub_keyboard_layout_engine.h
@@ -24,7 +24,6 @@ class EVENTS_OZONE_LAYOUT_EXPORT StubKeyboardLayoutEngine
   bool Lookup(DomCode dom_code,
               int flags,
               DomKey* dom_key,
-              base::char16* character,
               KeyboardCode* key_code,
               uint32* platform_keycode) const override;
 };
diff --git a/ui/events/ozone/layout/xkb/xkb_keyboard_code_conversion.cc b/ui/events/ozone/layout/xkb/xkb_keyboard_code_conversion.cc
deleted file mode 100644
index 69571c3..0000000
--- a/ui/events/ozone/layout/xkb/xkb_keyboard_code_conversion.cc
+++ /dev/null
@@ -1,84 +0,0 @@
-// 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_code_conversion.h"
-
-#include "ui/events/keycodes/dom/dom_key.h"
-
-namespace ui {
-
-base::char16 DeadXkbKeySymToCombiningCharacter(xkb_keysym_t keysym) {
-  switch (keysym) {
-    case XKB_KEY_dead_grave:
-      return 0x0300;  // combining grave accent
-    case XKB_KEY_dead_acute:
-      return 0x0301;  // combining acute accent
-    case XKB_KEY_dead_circumflex:
-      return 0x0302;  // combining circumflex accent
-    case XKB_KEY_dead_tilde:
-      return 0x0303;  // combining tilde
-    case XKB_KEY_dead_macron:
-      return 0x0304;  // combining macron
-    case XKB_KEY_dead_breve:
-      return 0x0306;  // combining breve
-    case XKB_KEY_dead_abovedot:
-      return 0x0307;  // combining dot above
-    case XKB_KEY_dead_diaeresis:
-      return 0x0308;  // combining diaeresis
-    case XKB_KEY_dead_abovering:
-      return 0x030A;  // combining ring above
-    case XKB_KEY_dead_doubleacute:
-      return 0x030B;  // combining double acute accent
-    case XKB_KEY_dead_caron:
-      return 0x030C;  // combining caron
-    case XKB_KEY_dead_cedilla:
-      return 0x0327;  // combining cedilla
-    case XKB_KEY_dead_ogonek:
-      return 0x0328;  // combining ogonek
-    case XKB_KEY_dead_iota:
-      return 0x0345;  // combining greek ypogegrammeni
-    case XKB_KEY_dead_voiced_sound:
-      return 0x3099;  // combining katakana-hiragana voiced sound mark
-    case XKB_KEY_dead_semivoiced_sound:
-      return 0x309A;  // combining katakana-hiragana semi-voiced sound mark
-    case XKB_KEY_dead_belowdot:
-      return 0x0323;  // combining dot below
-    case XKB_KEY_dead_hook:
-      return 0x0309;  // combining hook above
-    case XKB_KEY_dead_horn:
-      return 0x031B;  // combining horn
-    case XKB_KEY_dead_stroke:
-      return 0x0338;  // combining long solidus overlay
-    case XKB_KEY_dead_abovecomma:
-      return 0x0313;  // combining comma above
-    case XKB_KEY_dead_abovereversedcomma:
-      return 0x0314;  // combining reversed comma above
-    case XKB_KEY_dead_doublegrave:
-      return 0x030F;  // combining double grave accent
-    case XKB_KEY_dead_belowring:
-      return 0x0325;  // combining ring below
-    case XKB_KEY_dead_belowmacron:
-      return 0x0331;  // combining macron below
-    case XKB_KEY_dead_belowcircumflex:
-      return 0x032D;  // combining circumflex accent below
-    case XKB_KEY_dead_belowtilde:
-      return 0x0330;  // combining tilde below
-    case XKB_KEY_dead_belowbreve:
-      return 0x032E;  // combining breve below
-    case XKB_KEY_dead_belowdiaeresis:
-      return 0x0324;  // combining diaeresis below
-    case XKB_KEY_dead_invertedbreve:
-      return 0x0311;  // combining inverted breve
-    case XKB_KEY_dead_belowcomma:
-      return 0x0326;  // combining comma below
-    case XKB_KEY_dead_currency:
-      return 0x00A4;  // currency sign
-    case XKB_KEY_dead_greek:
-      return 0x037E;  // greek question mark
-    default:
-      return 0;
-  }
-}
-
-}  // namespace ui
diff --git a/ui/events/ozone/layout/xkb/xkb_keyboard_code_conversion.h b/ui/events/ozone/layout/xkb/xkb_keyboard_code_conversion.h
deleted file mode 100644
index 0fd5252..0000000
--- a/ui/events/ozone/layout/xkb/xkb_keyboard_code_conversion.h
+++ /dev/null
@@ -1,27 +0,0 @@
-// 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 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_
diff --git a/ui/events/ozone/layout/xkb/xkb_keyboard_layout_engine.cc b/ui/events/ozone/layout/xkb/xkb_keyboard_layout_engine.cc
index 3e393dc8..5307f73 100644
--- a/ui/events/ozone/layout/xkb/xkb_keyboard_layout_engine.cc
+++ b/ui/events/ozone/layout/xkb/xkb_keyboard_layout_engine.cc
@@ -19,7 +19,6 @@
 #include "ui/events/keycodes/dom/keycode_converter.h"
 #include "ui/events/keycodes/keyboard_code_conversion.h"
 #include "ui/events/keycodes/keyboard_code_conversion_xkb.h"
-#include "ui/events/ozone/layout/xkb/xkb_keyboard_code_conversion.h"
 
 namespace ui {
 
@@ -716,9 +715,8 @@ bool XkbKeyboardLayoutEngine::UsesAltGr() const {
 bool XkbKeyboardLayoutEngine::Lookup(DomCode dom_code,
                                      int flags,
                                      DomKey* dom_key,
-                                     base::char16* character,
                                      KeyboardCode* key_code,
-                                     uint32* platform_keycode) const {
+                                     uint32_t* platform_keycode) const {
   if (dom_code == DomCode::NONE)
     return false;
   // Convert DOM physical key to XKB representation.
@@ -732,30 +730,26 @@ bool XkbKeyboardLayoutEngine::Lookup(DomCode dom_code,
   xkb_mod_mask_t xkb_flags = EventFlagsToXkbFlags(flags);
   // Obtain keysym and character.
   xkb_keysym_t xkb_keysym;
-  if (!XkbLookup(xkb_keycode, xkb_flags, &xkb_keysym, character))
+  uint32_t character = 0;
+  if (!XkbLookup(xkb_keycode, xkb_flags, &xkb_keysym, &character))
     return false;
   *platform_keycode = xkb_keysym;
   // Classify the keysym and convert to DOM and VKEY representations.
   *dom_key = NonPrintableXKeySymToDomKey(xkb_keysym);
   if (*dom_key == DomKey::NONE) {
-    *dom_key = CharacterToDomKey(*character);
-    *key_code = AlphanumericKeyboardCode(*character);
+    *dom_key = DomKey::FromCharacter(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) {
+                                        xkb_keysym, character);
+      if (*key_code == VKEY_UNKNOWN)
         *key_code = LocatedToNonLocatedKeyboardCode(
             DomCodeToUsLayoutKeyboardCode(dom_code));
-      }
     }
     // 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 = LocatedToNonLocatedKeyboardCode(
-        DomCodeToUsLayoutKeyboardCode(dom_code));
+    if ((flags & EF_CONTROL_DOWN) && (character >= 0x20))
+      *dom_key = DomKey::UNIDENTIFIED;
   } else {
     *key_code = NonPrintableDomKeyToKeyboardCode(*dom_key);
     if (*key_code == VKEY_UNKNOWN) {
@@ -815,7 +809,7 @@ xkb_mod_mask_t XkbKeyboardLayoutEngine::EventFlagsToXkbFlags(
 bool XkbKeyboardLayoutEngine::XkbLookup(xkb_keycode_t xkb_keycode,
                                         xkb_mod_mask_t xkb_flags,
                                         xkb_keysym_t* xkb_keysym,
-                                        base::char16* character) const {
+                                        uint32_t* character) const {
   if (!xkb_state_) {
     LOG(ERROR) << "No current XKB state";
     return false;
@@ -824,9 +818,9 @@ bool XkbKeyboardLayoutEngine::XkbLookup(xkb_keycode_t xkb_keycode,
   *xkb_keysym = xkb_state_key_get_one_sym(xkb_state_.get(), xkb_keycode);
   if (*xkb_keysym == XKB_KEY_NoSymbol)
     return false;
-  uint32_t c = xkb_state_key_get_utf32(xkb_state_.get(), xkb_keycode);
-  DLOG_IF(ERROR, c != (c & 0xFFFF)) << "Non-BMP character:" << c;
-  *character = static_cast<base::char16>(c);
+  *character = xkb_state_key_get_utf32(xkb_state_.get(), xkb_keycode);
+  DLOG_IF(ERROR, *character != (*character & 0xFFFF))
+      << "Non-BMP character:" << *character;
   return true;
 }
 
@@ -836,19 +830,18 @@ KeyboardCode XkbKeyboardLayoutEngine::DifficultKeyboardCode(
     xkb_keycode_t xkb_keycode,
     xkb_mod_mask_t xkb_flags,
     xkb_keysym_t xkb_keysym,
-    DomKey dom_key,
     base::char16 character) const {
   // Get the layout interpretation without modifiers, so that
   // e.g. Ctrl+D correctly generates VKEY_D.
   xkb_keysym_t plain_keysym;
-  base::char16 plain_character;
+  uint32_t plain_character;
   if (!XkbLookup(xkb_keycode, 0, &plain_keysym, &plain_character))
     return VKEY_UNKNOWN;
 
   // If the plain key is non-printable, that determines the VKEY.
   DomKey plain_key = NonPrintableXKeySymToDomKey(plain_keysym);
   if (plain_key != ui::DomKey::NONE)
-    return NonPrintableDomKeyToKeyboardCode(dom_key);
+    return NonPrintableDomKeyToKeyboardCode(plain_key);
 
   // Plain ASCII letters and digits map directly to VKEY values.
   KeyboardCode key_code = AlphanumericKeyboardCode(plain_character);
@@ -911,7 +904,7 @@ base::char16 XkbKeyboardLayoutEngine::XkbSubCharacter(
   if (flags == base_flags)
     return base_character;
   xkb_keysym_t keysym;
-  base::char16 character = 0;
+  uint32_t character = 0;
   if (!XkbLookup(xkb_keycode, flags, &keysym, &character))
     character = kNone;
   return character;
diff --git a/ui/events/ozone/layout/xkb/xkb_keyboard_layout_engine.h b/ui/events/ozone/layout/xkb/xkb_keyboard_layout_engine.h
index 89729a0..ccc8d65 100644
--- a/ui/events/ozone/layout/xkb/xkb_keyboard_layout_engine.h
+++ b/ui/events/ozone/layout/xkb/xkb_keyboard_layout_engine.h
@@ -37,7 +37,6 @@ class EVENTS_OZONE_LAYOUT_EXPORT XkbKeyboardLayoutEngine
   bool Lookup(DomCode dom_code,
               int flags,
               DomKey* dom_key,
-              base::char16* character,
               KeyboardCode* key_code,
               uint32* platform_keycode) const override;
 
@@ -59,13 +58,12 @@ class EVENTS_OZONE_LAYOUT_EXPORT XkbKeyboardLayoutEngine
   // Determines the Windows-based KeyboardCode (VKEY) for a character key,
   // accounting for non-US layouts. May return VKEY_UNKNOWN, in which case the
   // caller should, as a last resort, obtain a KeyboardCode using
-  // |DomCodeToUsLayoutMeaning()|.
+  // |DomCodeToUsLayoutDomKey()|.
   KeyboardCode DifficultKeyboardCode(DomCode dom_code,
                                      int ui_flags,
                                      xkb_keycode_t xkb_keycode,
                                      xkb_mod_mask_t xkb_flags,
                                      xkb_keysym_t xkb_keysym,
-                                     DomKey dom_key,
                                      base::char16 character) const;
 
   // Maps DomCode to xkb_keycode_t.
@@ -89,7 +87,7 @@ class EVENTS_OZONE_LAYOUT_EXPORT XkbKeyboardLayoutEngine
   virtual bool XkbLookup(xkb_keycode_t xkb_keycode,
                          xkb_mod_mask_t xkb_flags,
                          xkb_keysym_t* xkb_keysym,
-                         base::char16* character) const;
+                         uint32_t* character) const;
 
   // Helper for difficult VKEY lookup. If |ui_flags| matches |base_flags|,
   // returns |base_character|; otherwise returns the XKB character for
diff --git a/ui/events/ozone/layout/xkb/xkb_keyboard_layout_engine_unittest.cc b/ui/events/ozone/layout/xkb/xkb_keyboard_layout_engine_unittest.cc
index 6701beb..17ae1d8 100644
--- a/ui/events/ozone/layout/xkb/xkb_keyboard_layout_engine_unittest.cc
+++ b/ui/events/ozone/layout/xkb/xkb_keyboard_layout_engine_unittest.cc
@@ -85,13 +85,12 @@ class VkTestXkbKeyboardLayoutEngine : public XkbKeyboardLayoutEngine {
                                base::char16 character) const {
     KeyboardCode key_code = DifficultKeyboardCode(
         dom_code, flags, key_code_converter_.DomCodeToXkbKeyCode(dom_code),
-        flags, CharacterToKeySym(character), DomKey::CHARACTER, character);
+        flags, CharacterToKeySym(character), character);
     if (key_code == VKEY_UNKNOWN) {
       DomKey dummy_dom_key;
-      base::char16 dummy_character;
       // If this fails, key_code remains VKEY_UNKNOWN.
-      ignore_result(DomCodeToUsLayoutMeaning(dom_code, EF_NONE, &dummy_dom_key,
-                                             &dummy_character, &key_code));
+      ignore_result(DomCodeToUsLayoutDomKey(dom_code, EF_NONE, &dummy_dom_key,
+                                             &key_code));
     }
     return key_code;
   }
@@ -100,7 +99,7 @@ class VkTestXkbKeyboardLayoutEngine : public XkbKeyboardLayoutEngine {
   bool XkbLookup(xkb_keycode_t xkb_keycode,
                  xkb_mod_mask_t xkb_flags,
                  xkb_keysym_t* xkb_keysym,
-                 base::char16* character) const override {
+                 uint32_t* character) const override {
     switch (entry_type_) {
       case EntryType::NONE:
         break;
@@ -817,11 +816,10 @@ TEST_F(XkbLayoutEngineVkTest, KeyboardCodeForNonPrintable) {
     SCOPED_TRACE(static_cast<int>(e.test.dom_code));
     layout_engine_->SetEntry(&e.test);
     DomKey dom_key = DomKey::NONE;
-    base::char16 character = 0;
     KeyboardCode key_code = VKEY_UNKNOWN;
     uint32_t keysym;
     EXPECT_TRUE(layout_engine_->Lookup(e.test.dom_code, EF_NONE, &dom_key,
-                                       &character, &key_code, &keysym));
+                                       &key_code, &keysym));
     EXPECT_EQ(e.test.keysym, keysym);
     EXPECT_EQ(e.key_code, key_code);
   }