Display "Restart to update" dialog to Chrome OS users.

ash/common/system/tray/system_tray_delegate.h

 // Copyright (c) 2012 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #ifndef ASH_COMMON_SYSTEM_TRAY_SYSTEM_TRAY_DELEGATE_H_
 #define ASH_COMMON_SYSTEM_TRAY_SYSTEM_TRAY_DELEGATE_H_
 
 #include <memory>
 #include <string>
 #include <vector>
@@ skipping 49 matching lines @@
     UPDATE_SEVERE,
     UPDATE_CRITICAL,
   };
 
   UpdateInfo();
   ~UpdateInfo();
 
   UpdateSeverity severity;
   bool update_required;
   bool factory_reset_required;
+  bool component_update_required;

[James Cook, 2016/11/30 23:01:41]

nit (if you keep this): Document this. Might be helpful to say that Flash is an
example component.

 };
 
 class CastConfigDelegate;
 class NetworkingConfigDelegate;
 
 // SystemTrayDelegate is intended for delegating tasks in the System Tray to the
 // application (e.g. Chrome). These tasks should be limited to application
 // (browser) specific tasks. For non application specific tasks, where possible,
 // components/, chromeos/, device/, etc., code should be used directly. If more
 // than one related method is being added, consider adding an additional
@@ skipping 139 matching lines @@
   // Creates a system tray item for display rotation lock.
   // TODO(jamescook): Remove this when mus has support for display management
   // and we have a DisplayManager equivalent. See http://crbug.com/548429
   virtual std::unique_ptr<SystemTrayItem> CreateRotationLockTrayItem(
       SystemTray* tray);
 };
 
 }  // namespace ash
 
 #endif  // ASH_COMMON_SYSTEM_TRAY_SYSTEM_TRAY_DELEGATE_H_