chromeos: Convert system tray session length limit to mojo

ash/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_SYSTEM_TRAY_SYSTEM_TRAY_DELEGATE_H_
 #define ASH_SYSTEM_TRAY_SYSTEM_TRAY_DELEGATE_H_
 
 #include <string>
 #include <vector>
 
 #include "ash/ash_export.h"
-#include "base/i18n/time_formatting.h"
 #include "base/strings/string16.h"
 
-namespace base {
-class TimeDelta;
-class TimeTicks;
-}
-
 namespace ash {
 struct IMEInfo;
 struct IMEPropertyInfo;
 
 using IMEInfoList = std::vector<IMEInfo>;
 using IMEPropertyInfoList = std::vector<IMEPropertyInfo>;
 
 class NetworkingConfigDelegate;
 
 // SystemTrayDelegate is intended for delegating tasks in the System Tray to the
@@ skipping 22 matching lines @@
 
   // Returns a list of properties for the currently selected IME.
   virtual void GetCurrentIMEProperties(IMEPropertyInfoList* list);
 
   // Returns a non-empty string if IMEs are managed by policy.
   virtual base::string16 GetIMEManagedMessage();
 
   // Returns NetworkingConfigDelegate. May return nullptr.
   virtual NetworkingConfigDelegate* GetNetworkingConfigDelegate() const;
 
-  // Retrieves the session start time. Returns |false| if the time is not set.
-  virtual bool GetSessionStartTime(base::TimeTicks* session_start_time);
-
-  // Retrieves the session length limit. Returns |false| if no limit is set.
-  virtual bool GetSessionLengthLimit(base::TimeDelta* session_length_limit);
-
   // The active user has been changed. This will be called when the UI is ready
   // to be switched to the new user.
   // Note: This will happen after SessionObserver::ActiveUserChanged fires.
   virtual void ActiveUserWasChanged();
 
   // Returns true when the Search key is configured to be treated as Caps Lock.
   virtual bool IsSearchKeyMappedToCapsLock();
 };
 
 }  // namespace ash
 
 #endif  // ASH_SYSTEM_TRAY_SYSTEM_TRAY_DELEGATE_H_