ChromeOS: implement per-user time zone preferences.

chrome/browser/chromeos/login/ui/login_display_host_impl.cc

Index: chrome/browser/chromeos/login/ui/login_display_host_impl.cc
diff --git a/chrome/browser/chromeos/login/ui/login_display_host_impl.cc b/chrome/browser/chromeos/login/ui/login_display_host_impl.cc
index 6db2b1af8b0e70bb4d47adbe482ba8dd6dcb53d3..3dfa4aacd5058a12a91ba352cfdd4992acd61802 100644
--- a/chrome/browser/chromeos/login/ui/login_display_host_impl.cc
+++ b/chrome/browser/chromeos/login/ui/login_display_host_impl.cc
@@ -189,21 +189,28 @@ void ShowLoginWizardFinish(
     chromeos::LoginDisplayHost* display_host) {
   TRACE_EVENT0("chromeos", "ShowLoginWizard::ShowLoginWizardFinish");
 
+  // Restore system timezone.
+  std::string timezone;
+  if (g_browser_process && g_browser_process->local_state()) {

[michaelpg, 2017/05/15 23:01:50]

this might be a silly question, but when does OOBE not have a browser process
and a LocalState?

[Alexander Alekseev, 2017/05/16 01:11:56]

In unit_tests, I suppose. We have similar check in ShowLoginWizard().
I'll try to remove this check and see what I get.

+    timezone = g_browser_process->local_state()->GetString(
+        prefs::kSigninScreenTimezone);
+  }
+
   if (ShouldShowSigninScreen(first_screen)) {
     display_host->StartSignInScreen(chromeos::LoginScreenContext());
   } else {
     display_host->StartWizard(first_screen);
-
     // Set initial timezone if specified by customization.
-    const std::string timezone_name = startup_manifest->initial_timezone();
-    VLOG(1) << "Initial time zone: " << timezone_name;
+    const std::string customization_timezone =
+        startup_manifest->initial_timezone();
     // Apply locale customizations only once to preserve whatever locale
     // user has changed to during OOBE.
-    if (!timezone_name.empty()) {
-      chromeos::system::TimezoneSettings::GetInstance()->SetTimezoneFromID(
-          base::UTF8ToUTF16(timezone_name));
-    }
+    if (!customization_timezone.empty())
+      timezone = customization_timezone;
   }
+  g_browser_process->local_state()->SetString(prefs::kSigninScreenTimezone,
+                                              timezone);

[stevenjb, 2017/05/15 17:08:02]

This should only be necessary inside the else, and only if
(!customization_timezone.empty()), correct?

[michaelpg, 2017/05/15 23:01:50]

Seems that way, and then we wouldn't need to read in the pref value before
setting it.

[Alexander Alekseev, 2017/05/16 01:11:56]

Done.

[Alexander Alekseev, 2017/05/16 01:11:56]

We still need to set system timezone value here.

+  chromeos::CrosSettings::Get()->SetString(chromeos::kSystemTimezone, timezone);

[stevenjb, 2017/05/15 17:08:02]

What if timezone is empty, should we still be setting this? Also, could you
document why we are setting the CrosSettings pref here?

[Alexander Alekseev, 2017/05/16 01:11:56]

You are right, we should probably use system::TimezoneSettings here.
Added check for timezone correctness.

 }
 
 struct ShowLoginWizardSwitchLanguageCallbackData {