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 Chrome OS.

[Luis Héctor Chávez, 2016/03/15 18:01:56]

You are currently returning a single JSON-encoded policy, but it looks like you
might eventually return multiple policies (making a wild guess based on the fact
that PolicyMap holds multiple policies).

If the long-term plan is to only send one, update the comment to read "Get the
policy from Chrome OS", otherwise change the callback type to string[] policy.
In any case, please expand this comment so that it documents more about the
encoding, the content of the policy, and the cardinality of policies.

[phweiss, 2016/03/16 18:45:12]

The "Policy" in GetPolicy and PolicyHost refers to the whole collection of
decisions by the admin, which is a list of values for our "policies" in the
technical sense. The string will be a single JSON-object that can contain values
for multiple policies. I added some more details to the comments.

[phweiss, 2016/03/17 15:52:59]

I reconsidered this, and renamed the function now to plural.

+  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();

[phweiss, 2016/03/17 15:52:59]

This function is now renamed to OnPolicyUpdated for consistency with
PolicyService.

 };