Create ash media delegate earlier during ash shell initialization

ash/mus/window_manager.cc

 // Copyright 2015 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/window_manager.h"
 
 #include <stdint.h>
 
 #include <utility>
 
@@ skipping 81 matching lines @@
   frame_decoration_values->maximized_client_area_insets = client_area_insets;
   frame_decoration_values->max_title_bar_button_width =
       NonClientFrameController::GetMaxTitleBarButtonWidth();
   window_manager_client_->SetFrameDecorationValues(
       std::move(frame_decoration_values));
 
   std::unique_ptr<ShellDelegate> shell_delegate(
       new ShellDelegateMus(base::MakeUnique<AppListPresenterStub>()));
   shell_.reset(new WmShellMus(std::move(shell_delegate), window_tree_client_,
                               connector_));
+  shell_->Initialize();
   lookup_.reset(new WmLookupMus);
 }
 
 void WindowManager::SetScreenLocked(bool is_locked) {
   // TODO: screen locked state needs to be persisted for newly added displays.
   for (auto& root_window_controller : root_window_controllers_) {
     WmWindowMus* non_lock_screen_containers_container =
         root_window_controller->GetWindowByShellWindowId(
             kShellWindowId_NonLockScreenContainersContainer);
     non_lock_screen_containers_container->mus_window()->SetVisible(!is_locked);
@@ skipping 184 matching lines @@
       FOR_EACH_OBSERVER(WindowManagerObserver, observers_,
                         OnAccelerator(id, event));
       break;
   }
 
   return ui::mojom::EventResult::HANDLED;
 }
 
 }  // namespace mus
 }  // namespace ash