mash: Port ash_sysui ShelfDelegateMus impl to mojo:ash.

ash/sysui/BUILD.gn

 # 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.
 
 import("//build/config/ui.gni")
 import("//mojo/public/tools/bindings/mojom.gni")
 import("//services/shell/public/cpp/service.gni")
 import("//services/shell/public/service_manifest.gni")
 
 source_set("lib") {
   sources = [
     "app_list_presenter_mus.cc",
     "app_list_presenter_mus.h",
     "keyboard_ui_mus.cc",
     "keyboard_ui_mus.h",
-    "shelf_delegate_mus.cc",
-    "shelf_delegate_mus.h",
     "shell_delegate_mus.cc",
     "shell_delegate_mus.h",
     "stub_context_factory.cc",
     "stub_context_factory.h",
     "sysui_application.cc",
     "sysui_application.h",
     "wallpaper_delegate_mus.cc",
     "wallpaper_delegate_mus.h",
   ]
 
@@ skipping 64 matching lines @@
     "//services/ui",
   ]
 
   # TODO: Load locale-specific strings and explicit resource dependencies.
   resources = [
     "$root_out_dir/ash_test_resources_100_percent.pak",
     "$root_out_dir/ash_test_resources_200_percent.pak",
     "$root_out_dir/ash_test_strings.pak",
   ]
 }