cros: Update rotation lock UI

ash/system/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_ROTATION_TRAY_ROTATION_LOCK_H_
 #define ASH_SYSTEM_ROTATION_TRAY_ROTATION_LOCK_H_
 
 #include "ash/display/screen_orientation_controller_chromeos.h"
 #include "ash/shell_observer.h"
 #include "ash/system/tray/tray_image_item.h"
@@ skipping 27 matching lines @@
   // TrayImageItem:
   void DestroyTrayView() override;
 
  protected:
   // TrayImageItem:
   bool GetInitialVisibility() override;
 
  private:
   friend class TrayRotationLockTest;
 
-  // True if |on_primary_display_|, maximize mode is enabled, and rotation is
-  // locked.
+  // Update tray image based on whether user rotation lock is enabled.
+  void UpdateTrayImage();
+
+  // True if |on_primary_display_|, maximize mode is enabled.
   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();
 
   DISALLOW_COPY_AND_ASSIGN(TrayRotationLock);
 };
 
 }  // namespace ash
 
 #endif  // ASH_SYSTEM_ROTATION_TRAY_ROTATION_LOCK_H_