Allow arc app to lock screen orientation in TouchView/Tablet mode

ash/display/screen_orientation_controller_chromeos.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_DISPLAY_SCREEN_ORIENTATION_CONTROLLER_CHROMEOS_H_
 #define ASH_DISPLAY_SCREEN_ORIENTATION_CONTROLLER_CHROMEOS_H_
 
 #include <map>
 
 #include "ash/ash_export.h"
@@ skipping 39 matching lines @@
   // Add/Remove observers.
   void AddObserver(Observer* observer);
   void RemoveObserver(Observer* observer);
 
   // Allows/unallows a window to lock the screen orientation.
   void LockOrientationForWindow(
       aura::Window* requesting_windowwindow,
       blink::WebScreenOrientationLockType lock_orientation);
   void UnlockOrientationForWindow(aura::Window* window);
 
+  // Unlock all and set the rotation back to the user specified rotation.
+  void UnlockAll();
+
   bool ScreenOrientationProviderSupported() const;
 
   bool ignore_display_configuration_updates() const {
     return ignore_display_configuration_updates_;
   }
 
   // True if |rotation_lock_| has been set and accelerometer updates should not
   // rotate the display.
   bool rotation_locked() const { return rotation_locked_; }
 
@@ skipping 108 matching lines @@
   // Tracks all windows that have requested a lock, as well as the requested
   // orientation.
   std::map<aura::Window*, blink::WebScreenOrientationLockType> locking_windows_;
 
   DISALLOW_COPY_AND_ASSIGN(ScreenOrientationController);
 };
 
 }  // namespace ash
 
 #endif  // ASH_DISPLAY_SCREEN_ORIENTATION_CONTROLLER_CHROMEOS_H_