mash: Port sysui's WallpaperDelegateMus to mojo:ash.

ash/mus/bridge/wm_shell_mus.cc

 // Copyright 2016 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/mus/bridge/wm_shell_mus.h"
 
 #include <utility>
 
 #include "ash/common/accelerators/accelerator_controller.h"
 #include "ash/common/keyboard/keyboard_ui.h"
@@ skipping 122 matching lines @@
 
   CreateMaximizeModeController();
 
   CreateMruWindowTracker();
 
   SetSystemTrayDelegate(base::WrapUnique(new DefaultSystemTrayDelegate));
 
   // TODO(jamescook): Port ash::sysui::KeyboardUIMus and use it here.
   SetKeyboardUI(KeyboardUI::Create());
 
-  // TODO(msw): Port WallpaperDelegateMus and support this (crbug.com/629605):
-  // wallpaper_delegate()->InitializeWallpaper();
+  wallpaper_delegate()->InitializeWallpaper();
 }
 
 WmShellMus::~WmShellMus() {
   // This order mirrors that of Shell.
 
   // Destroy maximize mode controller early on since it has some observers which
   // need to be removed.
   DeleteMaximizeModeController();
   DeleteToastManager();
   DeleteSystemTrayDelegate();
@@ skipping 282 matching lines @@
                     OnWindowActivated(gained_active, lost_active));
 }
 
 void WmShellMus::OnDidDestroyClient(ui::WindowTreeClient* client) {
   DCHECK_EQ(window_tree_client(), client);
   client->RemoveObserver(this);
 }
 
 }  // namespace mus
 }  // namespace ash