Migrate upgrade notifications to observer

chrome/browser/ui/ash/system_tray_client.cc

Index: chrome/browser/ui/ash/system_tray_client.cc
diff --git a/chrome/browser/ui/ash/system_tray_client.cc b/chrome/browser/ui/ash/system_tray_client.cc
index c4ff0ae233c295b4022f1083ece0c879ea8409e4..f0af4b8afdb20da62c2f81e57f9c6024751fd936 100644
--- a/chrome/browser/ui/ash/system_tray_client.cc
+++ b/chrome/browser/ui/ash/system_tray_client.cc
@@ -14,7 +14,6 @@
 #include "base/metrics/user_metrics.h"
 #include "chrome/browser/browser_process.h"
 #include "chrome/browser/browser_process_platform_part.h"
-#include "chrome/browser/chrome_notification_types.h"
 #include "chrome/browser/chromeos/accessibility/accessibility_util.h"
 #include "chrome/browser/chromeos/bluetooth/bluetooth_pairing_dialog.h"
 #include "chrome/browser/chromeos/login/help_app_launcher.h"
@@ -46,7 +45,6 @@
 #include "chromeos/network/tether_constants.h"
 #include "components/session_manager/core/session_manager.h"
 #include "components/user_manager/user_manager.h"
-#include "content/public/browser/notification_service.h"
 #include "content/public/common/service_manager_connection.h"
 #include "device/bluetooth/bluetooth_device.h"
 #include "extensions/browser/api/vpn_provider/vpn_service.h"
@@ -108,9 +106,6 @@ SystemTrayClient::SystemTrayClient() : binding_(this) {
   // be queued on |system_tray_|.
   g_browser_process->platform_part()->GetSystemClock()->AddObserver(this);
 
-  registrar_.Add(this, chrome::NOTIFICATION_UPGRADE_RECOMMENDED,
-                 content::NotificationService::AllSources());
-
   // If an upgrade is available at startup then tell ash about it.
   if (UpgradeDetector::GetInstance()->notify_upgrade())
     HandleUpdateAvailable();
@@ -483,19 +478,16 @@ void SystemTrayClient::OnSystemClockChanged(
   system_tray_->SetUse24HourClock(clock->ShouldUse24HourClock());
 }
 
-void SystemTrayClient::Observe(int type,
-                               const content::NotificationSource& source,
-                               const content::NotificationDetails& details) {
-  DCHECK_EQ(chrome::NOTIFICATION_UPGRADE_RECOMMENDED, type);
-  HandleUpdateAvailable();
-}
-
 ////////////////////////////////////////////////////////////////////////////////
 // UpgradeDetector::UpgradeObserver:
 void SystemTrayClient::OnUpdateOverCellularAvailable() {
   HandleUpdateOverCellularAvailable();
 }
 
+void SystemTrayClient::OnUpgradeRecommended() {
+  HandleUpdateAvailable();
+}
+
 ////////////////////////////////////////////////////////////////////////////////
 // policy::CloudPolicyStore::Observer
 void SystemTrayClient::OnStoreLoaded(policy::CloudPolicyStore* store) {