Refactors keyboard related code so mash can use a keyboard

ash/mus/sysui_application.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/sysui_application.h"
 
 #include "ash/desktop_background/desktop_background_controller.h"
 #include "ash/host/ash_window_tree_host_init_params.h"
 #include "ash/host/ash_window_tree_host_platform.h"
+#include "ash/mojo_shell.h"
 #include "ash/mus/shell_delegate_mus.h"
 #include "ash/mus/stub_context_factory.h"
 #include "ash/root_window_settings.h"
 #include "ash/shell.h"
 #include "ash/shell_init_params.h"
 #include "ash/shell_window_ids.h"
 #include "base/threading/sequenced_worker_pool.h"
 #include "components/mus/public/cpp/property_type_converters.h"
 #include "mash/wm/public/interfaces/container.mojom.h"
 #include "ui/aura/env.h"
@@ skipping 102 matching lines @@
     ui::RegisterPathProvider();
     ui::ResourceBundle::InitSharedInstanceWithLocale(
         "en-US", nullptr, ui::ResourceBundle::LOAD_COMMON_RESOURCES);
   }
 
   ~AshInit() { worker_pool_->Shutdown(); }
 
   aura::Window* root() { return ash::Shell::GetPrimaryRootWindow(); }
 
   void Initialize(mojo::Shell* shell) {
+    SetMojoShell(shell);
+
     aura_init_.reset(new views::AuraInit(shell, "views_mus_resources.pak"));
     views::WindowManagerConnection::Create(shell);
 
     gfx::Screen* screen = gfx::Screen::GetScreen();
     DCHECK(screen);
     gfx::Size size = screen->GetPrimaryDisplay().bounds().size();
 
     // Uninstall the ScreenMus installed by WindowManagerConnection, so that ash
     // installs and uses the ScreenAsh. This can be removed once ash learns to
     // talk to mus for managing displays.
@@ skipping 56 matching lines @@
 
 void SysUIApplication::Initialize(mojo::Shell* shell,
                                   const std::string& url,
                                   uint32_t id) {
   ash_init_.reset(new AshInit());
   ash_init_->Initialize(shell);
 }
 
 }  // namespace sysui
 }  // namespace ash