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 VideoHost {
-  // Notifies Chrome a request for ipc channel of video acceleration.
-  OnRequestArcVideoAcceleratorChannel() => (handle channel_handle);
+interface PolicyHost {
+  // Get policies from CrOs.
+  GetPolicy() => (string policy);
 };
 
-interface VideoInstance {
+interface PolicyInstance {
   // Establishes full-duplex communication with the host.
-  Init(VideoHost host_ptr);
+  Init(PolicyHost host_ptr);
+
+  // Indicates policy has changed
+  OnPolicyChanged();
 };