[ChromeOS] Expose keyboard remapping to signin screen.

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

Index: chrome/browser/ui/webui/chromeos/login/signin_screen_handler.cc
diff --git a/chrome/browser/ui/webui/chromeos/login/signin_screen_handler.cc b/chrome/browser/ui/webui/chromeos/login/signin_screen_handler.cc
index cf023763f334e81d2a5efb3dcdeb3b0cd3ce2f4e..228b61e1be5eff74f100455c9c0d03ab7d31db31 100644
--- a/chrome/browser/ui/webui/chromeos/login/signin_screen_handler.cc
+++ b/chrome/browser/ui/webui/chromeos/login/signin_screen_handler.cc
@@ -973,6 +973,7 @@ gfx::NativeWindow SigninScreenHandler::GetNativeWindow() {
 
 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,
@@ -1430,6 +1431,9 @@ void SigninScreenHandler::HandleFocusPod(const AccountId& account_id) {
     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);