[ChromeOS] Expose keyboard remapping to signin screen.

chrome/browser/ui/webui/chromeos/login/signin_screen_handler.cc

 // Copyright (c) 2013 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 "chrome/browser/ui/webui/chromeos/login/signin_screen_handler.h"
 
 #include <stddef.h>
 
 #include <algorithm>
 #include <vector>
@@ skipping 955 matching lines @@
 }
 
 gfx::NativeWindow SigninScreenHandler::GetNativeWindow() {
   if (native_window_delegate_)
     return native_window_delegate_->GetNativeWindow();
   return nullptr;
 }
 
 void SigninScreenHandler::RegisterPrefs(PrefRegistrySimple* registry) {
   registry->RegisterDictionaryPref(prefs::kUsersLRUInputMethod);
+  registry->RegisterStringPref(prefs::kFocusedPodUserId, std::string());

[Alexander Alekseev, 2017/02/22 00:41:22]

Could you also explain the idea behind this?
CL description does not say anything about it.

[xdai1, 2017/02/22 00:52:09]

kFocusedPodUserId is used to track the current focused user pod in the login
screen. It then will be used in GetRemappedKey() function in event_rewriter.cc
to get the mapping preference of the current focused user.

[Alexander Alekseev, 2017/02/22 01:04:47]

It seems to me that storing temporary (not statefull) data to local state is not
nice. Could you find another way of doing this?

For example, we can use OobeUI (through
LoginDisplayHost::default_host()->GetOobeUI() ) for that.

[xdai1, 2017/02/22 01:42:16]

Thanks. Done.

 }
 
 void SigninScreenHandler::OnCurrentScreenChanged(OobeScreen current_screen,
                                                  OobeScreen new_screen) {
   if (new_screen == OobeScreen::SCREEN_ACCOUNT_PICKER) {
     // Restore active IME state if returning to user pod row screen.
     input_method::InputMethodManager::Get()->SetState(ime_state_);
   }
 }
 
@@ skipping 437 matching lines @@
 }
 
 void SigninScreenHandler::HandleFocusPod(const AccountId& account_id) {
   proximity_auth::ScreenlockBridge::Get()->SetFocusedUser(account_id);
   if (delegate_)
     delegate_->CheckUserStatus(account_id);
   if (!test_focus_pod_callback_.is_null())
     test_focus_pod_callback_.Run();
 
   focused_pod_account_id_ = base::MakeUnique<AccountId>(account_id);
+  PrefService* const prefs = g_browser_process->local_state();
+  prefs->SetString(prefs::kFocusedPodUserId, account_id.GetGaiaId());
+  prefs->CommitPendingWrite();
 
   const user_manager::User* user =
       user_manager::UserManager::Get()->FindUser(account_id);
   // |user| may be nullptr in kiosk mode or unit tests.
   if (user && user->is_logged_in() && !user->is_active()) {
     ash::WmShell::Get()->GetSessionStateDelegate()->SwitchActiveUser(
         account_id);
   } else {
     SetUserInputMethod(account_id.GetUserEmail(), ime_state_.get());
     SetKeyboardSettings(account_id);
@@ skipping 194 matching lines @@
   rate.initial_delay_in_ms = auto_repeat_delay;
   rate.repeat_interval_in_ms = auto_repeat_interval;
   input_method::InputMethodManager::Get()
       ->GetImeKeyboard()
       ->SetAutoRepeatEnabled(true);
   input_method::InputMethodManager::Get()->GetImeKeyboard()->SetAutoRepeatRate(
       rate);
 }
 
 }  // namespace chromeos