mash: Migrate shelf app list button to wm common types

ash/shelf/shelf_layout_manager.cc

 // Copyright (c) 2012 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/shelf/shelf_layout_manager.h"
 
 #include <algorithm>
 #include <cmath>
 #include <cstring>
 #include <string>
@@ skipping 1013 matching lines @@
   // visible.
   return show_shelf_region_in_screen;
 }
 
 ShelfAutoHideState ShelfLayoutManager::CalculateAutoHideState(
     ShelfVisibilityState visibility_state) const {
   if (visibility_state != SHELF_AUTO_HIDE || !shelf_widget_ ||
       !shelf_widget_->shelf())
     return SHELF_AUTO_HIDE_HIDDEN;
 
-  Shell* shell = Shell::GetInstance();
   // Unhide the shelf only on the active screen when the AppList is shown
   // (crbug.com/312445).
-  if (shell->GetAppListTargetVisibility()) {
+  if (WmShell::Get()->GetAppListTargetVisibility()) {
     aura::Window* active_window = wm::GetActiveWindow();
     aura::Window* shelf_window = shelf_widget_->GetNativeWindow();
     if (active_window && shelf_window &&
         active_window->GetRootWindow() == shelf_window->GetRootWindow()) {
       return SHELF_AUTO_HIDE_SHOWN;
     }
   }
 
   if (shelf_widget_->status_area_widget() &&
       shelf_widget_->status_area_widget()->ShouldShowShelf())
@@ skipping 159 matching lines @@
   if (ash::MaterialDesignController::IsShelfMaterial()) {
     return (state.visibility_state == SHELF_AUTO_HIDE &&
             state.auto_hide_state == SHELF_AUTO_HIDE_SHOWN)
                ? 1.0f
                : 0.0f;
   }
   return (state.visibility_state == SHELF_AUTO_HIDE) ? 1.0f : 0.0f;
 }
 
 }  // namespace ash