Remove NOTIFICATION_SYSTEM_SETTING_CHANGED, switch CrosSettings to base::CallbackRegistry.

chrome/browser/chromeos/login/version_info_updater.cc

Index: chrome/browser/chromeos/login/version_info_updater.cc
diff --git a/chrome/browser/chromeos/login/version_info_updater.cc b/chrome/browser/chromeos/login/version_info_updater.cc
index 84ff2ce3dba8f6e4ef39829ce28d6d30e1644118..8f443ea03d3d95b1c7c40c00b3142bea65d5db02 100644
--- a/chrome/browser/chromeos/login/version_info_updater.cc
+++ b/chrome/browser/chromeos/login/version_info_updater.cc
@@ -27,17 +27,6 @@
 
 namespace chromeos {
 
-namespace {
-
-const char* kReportingFlags[] = {
-  chromeos::kReportDeviceVersionInfo,
-  chromeos::kReportDeviceActivityTimes,
-  chromeos::kReportDeviceBootMode,
-  chromeos::kReportDeviceLocation,
-};
-
-}
-
 ///////////////////////////////////////////////////////////////////////////////
 // VersionInfoUpdater public:
 
@@ -53,9 +42,6 @@ VersionInfoUpdater::~VersionInfoUpdater() {
           GetDeviceCloudPolicyManager();
   if (policy_manager)
     policy_manager->core()->store()->RemoveObserver(this);
-
-  for (unsigned int i = 0; i < arraysize(kReportingFlags); ++i)
-    cros_settings_->RemoveSettingsObserver(kReportingFlags[i], this);
 }
 
 void VersionInfoUpdater::StartUpdate(bool is_official_build) {
@@ -82,8 +68,22 @@ void VersionInfoUpdater::StartUpdate(bool is_official_build) {
   }
 
   // Watch for changes to the reporting flags.
-  for (unsigned int i = 0; i < arraysize(kReportingFlags); ++i)
-    cros_settings_->AddSettingsObserver(kReportingFlags[i], this);
+  version_info_subscription_ = cros_settings_->AddSettingsObserver(
+      kReportDeviceVersionInfo,
+      base::Bind(&VersionInfoUpdater::UpdateEnterpriseInfo,

[Lei Zhang, 2013/09/18 05:00:53]

Can you assign this to a base::Closure variable and re-use it in the 4 different
AddSettingsObserver() calls?

[Mattias Nissler (ping if slow), 2013/09/18 09:09:48]

Could also keep the array and loop in that case and switch to a ScopedVector for
the subscriptions.

[Avi (use Gerrit), 2013/09/18 16:41:44]

Done.

[Lei Zhang, 2013/09/18 18:51:07]

chrome/browser/chromeos/login/existing_user_controller.cc can probably use the
same treatment.

[Avi (use Gerrit), 2013/09/18 19:39:07]

If you look at ExistingUserControllerAutoLoginTest, it explicitly resets two of
the six notifications, so I'd have to use a loop for four notifications while
keeping those two separate. That's weird :(

+                 base::Unretained(this)));
+  activity_times_subscription_ = cros_settings_->AddSettingsObserver(
+      kReportDeviceActivityTimes,
+      base::Bind(&VersionInfoUpdater::UpdateEnterpriseInfo,
+                 base::Unretained(this)));
+  boot_mode_subscription_ = cros_settings_->AddSettingsObserver(
+      kReportDeviceBootMode,
+      base::Bind(&VersionInfoUpdater::UpdateEnterpriseInfo,
+                 base::Unretained(this)));
+  location_subscription_ = cros_settings_->AddSettingsObserver(
+      kReportDeviceLocation,
+      base::Bind(&VersionInfoUpdater::UpdateEnterpriseInfo,
+                 base::Unretained(this)));
 }
 
 void VersionInfoUpdater::UpdateVersionLabel() {
@@ -134,14 +134,4 @@ void VersionInfoUpdater::OnStoreError(policy::CloudPolicyStore* store) {
   UpdateEnterpriseInfo();
 }
 
-void VersionInfoUpdater::Observe(
-    int type,
-    const content::NotificationSource& source,
-    const content::NotificationDetails& details) {
-  if (type == chrome::NOTIFICATION_SYSTEM_SETTING_CHANGED)
-    UpdateEnterpriseInfo();
-  else
-    NOTREACHED();
-}
-
 }  // namespace chromeos