Callback to function InitializeRegisteredDeviceWallpaper after cros settings can be trusted

chrome/browser/chromeos/login/wallpaper_manager.cc

Index: chrome/browser/chromeos/login/wallpaper_manager.cc
diff --git a/chrome/browser/chromeos/login/wallpaper_manager.cc b/chrome/browser/chromeos/login/wallpaper_manager.cc
index f73eff1b80a9f7c088db23a06e6bc909808a0d9f..5cb92f8319222cb6883bf7f54ca13773cc1cbce0 100644
--- a/chrome/browser/chromeos/login/wallpaper_manager.cc
+++ b/chrome/browser/chromeos/login/wallpaper_manager.cc
@@ -244,6 +244,12 @@ void WallpaperManager::InitializeWallpaper() {
       if (!WizardController::IsDeviceRegistered()) {
         SetDefaultWallpaper();
       } else {
+        if (CrosSettingsProvider::TEMPORARILY_UNTRUSTED ==

[bshe, 2012/12/04 20:13:14]

girard@ and I came up with this to take care of the PERMANENTLY_UNTRUSTED
situation. If the setting is permanently untrusted, we should just proceed with
whatever value we get from settings or default to show user pod if we failed to
get value out from setting.

We assumed that it is OK to use the value in settings when status is
PERMANENTLY_UNTRUSTED and that value wont change to something else when we
initialize login webui (and try to get the same value in setttings again).

[bartfab (slow), 2012/12/06 13:57:01]

Normally, PERMANENTLY_UNTRUSTED means that we are missing some crucial bit of
the crypto chain (read: the owner key) and will never be able to verify settings
- hence, permanently untrusted.

However, during enrollment, the situation is different. When you first boot up a
brand new device, its settings are PERMANENTLY_UNTRUSTED because there is no
owner key and the policy system cannot verify any settings. Once you go through
enrollment though, an owner key suddenly appears and the status jumps from
PERMANENTLY_UNTRUSTED to TRUSTED.

You may choose to just not handle this. After a reboot, the device will behave
as expected, going through the TEMPORARILY_UNTRUSTED and TRUSTED states only. Or
you can handle it gracefully: Register an observer for the wallpaper pref. When
the value changes, you should fire off another trustedness check. If the device
has just gone through enrollment, you will now get trusted values, even if they
were PERMANENTLY_UNTRUSTED before.

My CL I pointed you at in our discussion does exactly this. Note though that
right now, the settings will still appear PERMANENTLY_UNTRUSTED when that
observer fires. This is a bug and I will be landing CL 11421099 RSN to fix it.

+            CrosSettings::Get()->PrepareTrustedValues(
+                base::Bind(&WallpaperManager::InitializeWallpaper,
+                           base::Unretained(this)))) {
+          return;
+        }
         bool show_users = true;
         bool result = CrosSettings::Get()->GetBoolean(
             kAccountsPrefShowUserNamesOnSignIn, &show_users);