cros: Treat set rotation for chrome.system.display API in touchview mode as if user rotation lock

ash/display/screen_orientation_controller_chromeos.h

Index: ash/display/screen_orientation_controller_chromeos.h
diff --git a/ash/display/screen_orientation_controller_chromeos.h b/ash/display/screen_orientation_controller_chromeos.h
index 069d5177930178938e58920975fd900ae3edb449..04121172638eec72d7219df3124d94b97dc4494f 100644
--- a/ash/display/screen_orientation_controller_chromeos.h
+++ b/ash/display/screen_orientation_controller_chromeos.h
@@ -79,6 +79,9 @@ class ASH_EXPORT ScreenOrientationController
   // user rotation lock.
   void ToggleUserRotationLock();
 
+  // Set locked to the given |rotation| and save it.
+  void SetLockToRotation(display::Display::Rotation rotation);
+
   // aura::client::ActivationChangeObserver:
   void OnWindowActivated(ActivationReason reason,
                          aura::Window* gained_active,
@@ -110,6 +113,9 @@ class ASH_EXPORT ScreenOrientationController
 
   void SetRotationLockedInternal(bool rotation_locked);
 
+  // A helper method that set locked to the given |orientation| and save it.
+  void SetLockToOrientation(blink::WebScreenOrientationLockType orientation);
+
   // Sets the display rotation to |rotation|. Future accelerometer updates
   // should not be used to change the rotation. SetRotationLocked(false) removes
   // the rotation lock.