Implement Stub for policy bridge to ARC

components/arc/common/policy.mojom

+// Copyright 2016 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.
+
+module arc;
+
+interface PolicyHost {
+  // Get policies from Chrome OS, as JSON-encoded dictionary with the policies'
+  // names as keys and their values as values. The list of possible policies can
+  // be found in components/policy/resources/policy_templates.json
+  GetPolicy() => (string policy);
+};
+
+interface PolicyInstance {
+  // Establishes full-duplex communication with the host.
+  Init(PolicyHost host_ptr);
+
+  // Indicates policy has changed
+  OnPolicyChanged();
+};