Moterm part 2: Add MotermDriver, a terminal "driver".

apps/moterm/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")
 
+source_set("driver") {
+  sources = [
+    "moterm_driver.cc",
+    "moterm_driver.h",
+  ]
+
+  public_deps = [
+    "//base",
+    "//mojo/public/cpp/bindings",
+    "//mojo/services/files/public/interfaces",
+  ]
+}
+
 source_set("model") {
   sources = [
     "moterm_model.cc",
     "moterm_model.h",
   ]
 
   deps = [
     "//third_party/libteken",
   ]
 
   forward_dependent_configs_from = [ "//third_party/libteken" ]
 
   public_deps = [
     "//base",
   ]
 }
 
 mojo_native_application("apptests") {
   output_name = "moterm_apptests"
 
   testonly = true
 
   sources = [
+    "moterm_driver_unittest.cc",
     "moterm_model_unittest.cc",
   ]
 
   deps = [
+    ":driver",
     ":model",
     "//mojo/application",
     "//mojo/application:test_support",
+    "//mojo/public/cpp/bindings:callback",
     "//testing/gtest",
   ]
 }