Add a new AssociationState DEPROVISIONED for cloud policy.

This adds a new enum value to Policy.AssociationState, indicating that
the server side dropped the client from management. The association
state is now also surfaced in the Status line in about:policy.

BUG=chromium:329834

Review URL: https://codereview.chromium.org/117253002

git-svn-id: http://src.chromium.org/svn/trunk/src/chrome/browser/policy/proto@242099 4ff67af0-8c30-449e-8e8b-ad334ec8d88c
diff --git a/cloud/device_management_backend.proto b/cloud/device_management_backend.proto
index dce49a6..7bda9e6 100644
--- a/cloud/device_management_backend.proto
+++ b/cloud/device_management_backend.proto
@@ -229,6 +229,8 @@
     ACTIVE = 0;
     // Association is alive, but the corresponding domain is not managed.
     UNMANAGED = 1;
+    // Client got dropped on the server side.
+    DEPROVISIONED = 2;
   }
   optional AssociationState state = 9 [default = ACTIVE];