Implement basic mojo Permission service and use it for Geolocation.

content/common/permission_service.mojom

+// Copyright 2014 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 content;
+
+enum PermissionStatus {
+  GRANTED,
+  DENIED,
+  ASK
+};
+
+enum PermissionName {
+  GEOLOCATION,
+};
+
+// The Permission service provides permission handling capabilities by exposing
+// methods to check, request, and revoke permissions. It also allows a client to
+// start listening to permission changes.
+interface PermissionService {
+  QueryPermission(PermissionName permission, string origin)
+    => (PermissionStatus status);
+  RequestPermission(PermissionName permission, string origin)

[blundell, 2014/11/14 14:42:00]

You might want to specify that this returns the current permission status if the
service is not in a context where it can ask the user for permissions?

[mlamouri (slow - plz ping), 2014/11/14 16:14:45]

I would consider this an implementation detail. As far as the caller is
concerned, the new permission status is returned.

+    => (PermissionStatus status);
+//   RevokePermission(PermissionName permission, string origin)

[qsr, 2014/11/14 14:28:18]

Can you delete the lines instead of using comments.

[blundell, 2014/11/14 14:42:00]

I would kill all of this rather than land commented-out code.

[mlamouri (slow - plz ping), 2014/11/14 16:14:45]

Done.

+//     => (PermissionStatus status);
+
+//  StartObserving(PermissionName permission, string origin);
+//  StopObserving(PermissionName permission, string origin);
+};
+
+// interface PermissionServiceClient {
+//   OnPermissionChange(PermissionName permission,
+//                      string origin,
+//                      PermissionStatus status);
+// };