mash: Add touch-hud app.

mash/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("//services/shell/public/service_manifest.gni")
 import("//testing/test.gni")
 
 # Target that builders build.
 group("all") {
   testonly = true
 
   deps = [
     ":mash_unittests",
+    "//ash/touch_hud/mus:touch_hud",
     "//components/leveldb",
     "//mash/catalog_viewer",
     "//mash/example",
     "//mash/init",
     "//mash/login",
     "//mash/screenlock",
     "//mash/session",
     "//mash/task_viewer",
   ]
 }
@@ skipping 29 matching lines @@
     ":unittests_manifest",
     "//ash/mus:resources",
   ]
 }
 
 service_manifest("unittests_manifest") {
   type = "exe"
   name = "mash_unittests"
   source = "unittests_manifest.json"
 }