Add ShellDelegate, MediaDelegate and KeyboardUI stubs to mus ash

ash/mus/shell_delegate_mus.h

Index: ash/mus/shell_delegate_mus.h
diff --git a/ash/sysui/shell_delegate_mus.h b/ash/mus/shell_delegate_mus.h
similarity index 86%
copy from ash/sysui/shell_delegate_mus.h
copy to ash/mus/shell_delegate_mus.h
index c5323bc1b08f3a951d0e359a4a3699ca507f4e4a..e6dce759f067e426153470f8e9d9af95471cd488 100644
--- a/ash/sysui/shell_delegate_mus.h
+++ b/ash/mus/shell_delegate_mus.h
@@ -2,27 +2,23 @@
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
-#ifndef ASH_SYSUI_SHELL_DELEGATE_MUS_H_
-#define ASH_SYSUI_SHELL_DELEGATE_MUS_H_
+#ifndef ASH_MUS_SHELL_DELEGATE_MUS_H_
+#define ASH_MUS_SHELL_DELEGATE_MUS_H_
 
 #include <memory>
 
 #include "ash/common/shell_delegate.h"
 #include "base/macros.h"
 
-namespace keyboard {
-class KeyboardUI;
+namespace app_list {
+class AppListPresenter;
 }
 
 namespace ash {
 
-class AppListPresenterMus;
-
-namespace sysui {
-
 class ShellDelegateMus : public ShellDelegate {
  public:
-  explicit ShellDelegateMus(std::unique_ptr<AppListPresenterMus>);
+  explicit ShellDelegateMus(std::unique_ptr<app_list::AppListPresenter>);
   ~ShellDelegateMus() override;
 
   bool IsFirstRunAfterBoot() const override;
@@ -58,7 +54,6 @@ class ShellDelegateMus : public ShellDelegate {
   DISALLOW_COPY_AND_ASSIGN(ShellDelegateMus);
 };
 
-}  // namespace sysui
 }  // namespace ash
 
-#endif  // ASH_SYSUI_SHELL_DELEGATE_MUS_H_
+#endif  // ASH_MUS_SHELL_DELEGATE_MUS_H_