Remove enterprise serial number recovery feature

components/policy/proto/device_management_backend.proto

Index: components/policy/proto/device_management_backend.proto
diff --git a/components/policy/proto/device_management_backend.proto b/components/policy/proto/device_management_backend.proto
index d35f326864c7026ae0c79688e267fdfc9586eb8d..3cfe6a5efc874b7f85f916e2bca1f4934ec9fa94 100644
--- a/components/policy/proto/device_management_backend.proto
+++ b/components/policy/proto/device_management_backend.proto
@@ -340,11 +340,8 @@ message PolicyData {
   }
   optional AssociationState state = 9 [default = ACTIVE];
 
-  // Indicates if the the server cannot find a valid serial number for the
-  // device.  If this flag is set, the device should send the valid serial
-  // number with a device policy fetch request.  Note that this only
-  // applies to device policy.
-  optional bool valid_serial_number_missing = 10;
+  // OBSELETE: Serial number recovery is no longer supported.

[Thiemo Nagel, 2017/05/02 10:53:06]

We have changed our approach and now completely remove obsolete fields (but mark
their ids as reserved to avoid re-use.)

[pmarko, 2017/05/17 16:00:21]

Done.

+  optional bool OBSOLETE_valid_serial_number_missing = 10;
 
   // Indicates which public account or extension/plug-in this policy data is
   // for. See PolicyFetchRequest.settings_entity_id for more details.