Bug 676404 - command API migration. Fixes 845ed0ee7123. a=bustage

services/sync/modules/engines/clients.js

@@ -257,7 +257,7 @@ ClientEngine.prototype = {
    * @return false to abort sync
    */
   processIncomingCommands: function processIncomingCommands() {
-    this._notify("clients:process-commands", "", function() {
+    return this._notify("clients:process-commands", "", function() {
       let commands = this.localCommands;
 
       // Immediately clear out the commands as we've got them locally.

services/sync/tests/unit/test_clients_engine.js

@@ -387,7 +387,8 @@ add_test(function test_process_incoming_commands() {
 
   Svc.Obs.add(ev, handler);
 
-  Clients.processIncomingCommands();
+  // logout command causes processIncomingCommands to return explicit false.
+  do_check_false(Clients.processIncomingCommands());
 });
 
 add_test(function test_command_sync() {