Adds TraySessionLengthLimitTest to ash_unittests.

ash/system/session_length_limit/tray_session_length_limit.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_SESSION_LENGTH_LIMIT_TRAY_SESSION_LENGTH_LIMIT_H_
 #define ASH_SYSTEM_SESSION_LENGTH_LIMIT_TRAY_SESSION_LENGTH_LIMIT_H_
 
 #include "ash/system/session_length_limit/session_length_limit_observer.h"
 #include "ash/system/tray/system_tray_item.h"
 #include "base/basictypes.h"
 #include "base/compiler_specific.h"
 #include "base/memory/scoped_ptr.h"
 #include "base/time/time.h"
 #include "base/timer/timer.h"
 
 namespace ash {
+
+namespace test {
+class TraySessionLengthLimitTest;
+}
+
 namespace internal {
 
 namespace tray {
 class RemainingSessionTimeTrayView;
 }
 
 // Adds a countdown timer to the system tray if the session length is limited.
-class TraySessionLengthLimit : public SystemTrayItem,
-                               public SessionLengthLimitObserver {
+class ASH_EXPORT TraySessionLengthLimit : public SystemTrayItem,
+                                          public SessionLengthLimitObserver {
  public:
   enum LimitState {
     LIMIT_NONE,
     LIMIT_SET,
     LIMIT_EXPIRING_SOON
   };
 
   explicit TraySessionLengthLimit(SystemTray* system_tray);
   virtual ~TraySessionLengthLimit();
 
   // SystemTrayItem:
   virtual views::View* CreateTrayView(user::LoginStatus status) OVERRIDE;
   virtual void DestroyTrayView() OVERRIDE;
   virtual void UpdateAfterShelfAlignmentChange(
       ShelfAlignment alignment) OVERRIDE;
 
   // SessionLengthLimitObserver:
   virtual void OnSessionStartTimeChanged() OVERRIDE;
   virtual void OnSessionLengthLimitChanged() OVERRIDE;
 
   LimitState GetLimitState() const;
   base::TimeDelta GetRemainingSessionTime() const;
 
  private:
+  friend class test::TraySessionLengthLimitTest;
+
+  static const char kNotificationId[];
+
   void Update();
 
+  bool IsTrayViewVisibleForTest();
+
   tray::RemainingSessionTimeTrayView* tray_view_;
 
   LimitState limit_state_;
   base::TimeTicks session_start_time_;
   base::TimeDelta limit_;
   base::TimeDelta remaining_session_time_;
   scoped_ptr<base::RepeatingTimer<TraySessionLengthLimit> > timer_;
 
   DISALLOW_COPY_AND_ASSIGN(TraySessionLengthLimit);
 };
 
 }  // namespace internal
 }  // namespace ash
 
 #endif  // ASH_SYSTEM_SESSION_LENGTH_LIMIT_TRAY_SESSION_LENGTH_LIMIT_H_