mash: Port mojo:ash_sysui's ContextMenuMus to mojo:ash.

ash/sysui/shell_delegate_mus.cc

Index: ash/sysui/shell_delegate_mus.cc
diff --git a/ash/sysui/shell_delegate_mus.cc b/ash/sysui/shell_delegate_mus.cc
index a93abd68c4e3188453bc2f863b4feef408eef1bd..26cad2f97723623e1809bbb29104b876b3c2ea3c 100644
--- a/ash/sysui/shell_delegate_mus.cc
+++ b/ash/sysui/shell_delegate_mus.cc
@@ -10,10 +10,10 @@
 #include "ash/common/palette_delegate.h"
 #include "ash/common/session/session_state_delegate.h"
 #include "ash/common/system/tray/default_system_tray_delegate.h"
+#include "ash/mus/context_menu_mus.h"
 #include "ash/sysui/app_list_presenter_mus.h"
-#include "ash/sysui/context_menu_mus.h"
 #include "ash/sysui/shelf_delegate_mus.h"
-#include "ash/sysui/user_wallpaper_delegate_mus.h"
+#include "ash/sysui/wallpaper_delegate_mus.h"
 #include "base/memory/ptr_util.h"
 #include "base/strings/string16.h"
 #include "components/user_manager/user_info_impl.h"
@@ -171,8 +171,8 @@ SystemTrayDelegate* ShellDelegateMus::CreateSystemTrayDelegate() {
   return new DefaultSystemTrayDelegate;
 }
 
-UserWallpaperDelegate* ShellDelegateMus::CreateUserWallpaperDelegate() {
-  return new UserWallpaperDelegateMus();
+std::unique_ptr<WallpaperDelegate> ShellDelegateMus::CreateWallpaperDelegate() {
+  return base::MakeUnique<WallpaperDelegateMus>();
 }
 
 SessionStateDelegate* ShellDelegateMus::CreateSessionStateDelegate() {
@@ -202,7 +202,8 @@ std::unique_ptr<PaletteDelegate> ShellDelegateMus::CreatePaletteDelegate() {
 
 ui::MenuModel* ShellDelegateMus::CreateContextMenu(WmShelf* wm_shelf,
                                                    const ShelfItem* item) {
-  return new ContextMenuMus(wm_shelf);
+  NOTIMPLEMENTED();
+  return nullptr;
 }
 
 GPUSupport* ShellDelegateMus::CreateGPUSupport() {