Add ArcEnabled policy implementation

components/arc/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/tools/bindings/mojom.gni")
 
 static_library("arc") {
   sources = [
     "arc_bridge_bootstrap.cc",
     "arc_bridge_bootstrap.h",
@@ skipping 65 matching lines @@
     "common/settings.mojom",
     "common/video.mojom",
   ]
 }
 
 static_library("arc_test_support") {
   testonly = true
   sources = [
     "test/fake_app_instance.cc",
     "test/fake_app_instance.h",
+    "test/fake_arc_bridge_bootstrap.cc",
+    "test/fake_arc_bridge_bootstrap.h",
     "test/fake_arc_bridge_instance.cc",
     "test/fake_arc_bridge_instance.h",
     "test/fake_arc_bridge_service.cc",
     "test/fake_arc_bridge_service.h",
   ]
 
   deps = [
     ":arc",
     ":arc_bindings",
     "//base",
@@ skipping 18 matching lines @@
     "//mojo/public/cpp/environment:environment",
     "//mojo/public/cpp/system:system",
     "//testing/gtest",
     "//ui/aura",
     "//ui/base:test_support",
     "//ui/base/ime",
     "//ui/events",
     "//ui/events:dom_keycode_converter",
   ]
 }