Make RotationLockDefaultView inherit directly from ActionableView

ash/system/chromeos/rotation/tray_rotation_lock.h

 // Copyright 2014 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_CHROMEOS_ROTATION_TRAY_ROTATION_LOCK_H_
 #define ASH_SYSTEM_CHROMEOS_ROTATION_TRAY_ROTATION_LOCK_H_
 
 #include "ash/common/shell_observer.h"
 #include "ash/common/system/tray/tray_image_item.h"
 #include "ash/display/screen_orientation_controller_chromeos.h"
@@ skipping 38 matching lines @@
   // locked.
   bool ShouldBeVisible();
 
   // True if this is owned by a SystemTray on the primary display.
   bool OnPrimaryDisplay() const;
 
   // Removes TrayRotationLock as a ScreenOrientationController::Observer if
   // currently observing.
   void StopObservingRotation();
 
-  // Removes TrayRotationLock as a ShellObserver if currently observing.
-  void StopObservingShell();
-
-  // True while added as a ScreenOrientationController::Observer.
-  bool observing_rotation_;
-
-  // True while added as a ShellObserver.
-  bool observing_shell_;
-
   DISALLOW_COPY_AND_ASSIGN(TrayRotationLock);
 };
 
 }  // namespace ash
 
 #endif  // ASH_SYSTEM_CHROMEOS_ROTATION_TRAY_ROTATION_LOCK_H_