Reify view ownership as a message pipe.

examples/moterm_example_app/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("//mojo/public/mojo_application.gni")
 
 mojo_native_application("moterm_example_app") {
   sources = [
     "moterm_example_app.cc",
   ]
 
   deps = [
     "//base",
     "//mojo/application",
     "//mojo/common",
     "//mojo/public/cpp/bindings",
     "//mojo/public/cpp/utility",
     "//mojo/public/interfaces/application",
     "//mojo/services/files/interfaces",
     "//mojo/services/geometry/interfaces",
     "//mojo/services/terminal/interfaces",
     "//mojo/services/ui/views/interfaces",
+    "//mojo/ui",
   ]
 }