Use MD-ash's auto hide behavior for arc++ windows.

ash/wm/immersive_fullscreen_controller.cc

 // Copyright 2013 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.
 
 #include "ash/wm/immersive_fullscreen_controller.h"
 
 #include <set>
 
 #include "ash/common/ash_constants.h"
 #include "ash/common/wm/immersive/wm_immersive_fullscreen_controller_delegate.h"
@@ skipping 253 matching lines @@
 void ImmersiveFullscreenController::SetEnabled(WindowType window_type,
                                                bool enabled) {
   if (enabled_ == enabled)
     return;
   enabled_ = enabled;
 
   EnableWindowObservers(enabled_);
 
   ash::wm::WindowState* window_state = wm::GetWindowState(native_window_);
   // Auto hide the shelf in immersive fullscreen instead of hiding it.
-  window_state->set_hide_shelf_when_fullscreen(!enabled);
+  window_state->set_shelf_mode_in_fullscreen(
+      enabled ? ash::wm::WindowState::SHELF_AUTO_HIDE_VISIBLE
+              : ash::wm::WindowState::SHELF_HIDDEN);
 
   // Update the window's immersive mode state for the window manager.
   window_state->set_in_immersive_fullscreen(enabled);
 
   Shell::GetInstance()->UpdateShelfVisibility();
 
   if (enabled_) {
     // Animate enabling immersive mode by sliding out the top-of-window views.
     // No animation occurs if a lock is holding the top-of-window views open.
 
@@ skipping 633 matching lines @@
       ::wm::GetTransientChildren(native_window_);
   for (size_t i = 0; i < transient_children.size(); ++i) {
     aura::Window* transient_child = transient_children[i];
     views::View* anchor_view = GetAnchorView(transient_child);
     if (anchor_view && top_container_->Contains(anchor_view))
       bubble_observer_->StartObserving(transient_child);
   }
 }
 
 }  // namespace ash