Add rudimentary mash shelf functionality.

mash/shell/BUILD.gn

 # 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.
 
 import("//build/config/ui.gni")
 import("//mojo/public/mojo_application.gni")
 import("//mojo/public/tools/bindings/mojom.gni")
 import("//tools/grit/repack.gni")
 
 mojo_native_application("shell") {
   output_name = "mash_shell"
 
   sources = [
     "main.cc",
     "shell_application_delegate.cc",
     "shell_application_delegate.h",
   ]
 
   deps = [
     "//base",
     "//mojo/public/cpp/bindings",
     "//mojo/shell/public/cpp",
     "//mojo/shell/public/cpp:sources",
   ]
 
   data_deps = [
     "//mash/browser_driver",
-    "//mash/system_ui",
+    "//mash/quick_launch",
+    "//mash/shelf",
+    "//mash/wallpaper",
     "//mash/wm",
   ]
 }