ash: Use system tray mojo interface to show system update tray icon

chrome/browser/ui/ash/system_tray_delegate_chromeos.h

Index: chrome/browser/ui/ash/system_tray_delegate_chromeos.h
diff --git a/chrome/browser/ui/ash/system_tray_delegate_chromeos.h b/chrome/browser/ui/ash/system_tray_delegate_chromeos.h
index bb839411a35b3f4c5f6573d624daed982d621245..012ac31347e959ff3ad61a442fe173685aa44ca8 100644
--- a/chrome/browser/ui/ash/system_tray_delegate_chromeos.h
+++ b/chrome/browser/ui/ash/system_tray_delegate_chromeos.h
@@ -70,10 +70,6 @@ class SystemTrayDelegateChromeOS
 
   ~SystemTrayDelegateChromeOS() override;
 
-  // Access a global pointer to the single instance of the
-  // SystemTrayDelegateChromeOS class.
-  static SystemTrayDelegateChromeOS* instance();
-
   void InitializeOnAdapterReady(
       scoped_refptr<device::BluetoothAdapter> adapter);
 
@@ -88,7 +84,6 @@ class SystemTrayDelegateChromeOS
   base::string16 GetSupervisedUserMessage() const override;
   bool IsUserSupervised() const override;
   bool IsUserChild() const override;
-  void GetSystemUpdateInfo(ash::UpdateInfo* info) const override;
   bool ShouldShowSettings() const override;
   bool ShouldShowNotificationTray() const override;
   void ShowEnterpriseInfo() override;
@@ -127,11 +122,6 @@ class SystemTrayDelegateChromeOS
 
   void UserChangedChildStatus(user_manager::User* user) override;
 
-  // This notifies the system that a flash update is now available, and so the
-  // user should reboot.
-  void SetFlashUpdateAvailable();
-  bool GetFlashUpdateAvailable();
-
  private:
   ash::SystemTrayNotifier* GetSystemTrayNotifier();
 
@@ -244,7 +234,6 @@ class SystemTrayDelegateChromeOS
   std::string enterprise_realm_;
   bool should_run_bluetooth_discovery_ = false;
   bool session_started_ = false;
-  bool flash_update_available_ = false;
 
   scoped_refptr<device::BluetoothAdapter> bluetooth_adapter_;
   std::unique_ptr<device::BluetoothDiscoverySession>