Introduce the plumbing necessary to report Unrecoverable error from model safe workers.

chrome/browser/sync/engine/model_changing_syncer_command.cc

 // Copyright (c) 2011 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.
 
 #include "chrome/browser/sync/engine/model_changing_syncer_command.h"
 
+#include "base/basictypes.h"
 #include "base/callback_old.h"
 #include "chrome/browser/sync/engine/model_safe_worker.h"
 #include "chrome/browser/sync/sessions/status_controller.h"
 #include "chrome/browser/sync/sessions/sync_session.h"
+#include "chrome/browser/sync/util/unrecoverable_error_info.h"
 
 namespace browser_sync {
 
 void ModelChangingSyncerCommand::ExecuteImpl(sessions::SyncSession* session) {
   work_session_ = session;
   if (!ModelNeutralExecuteImpl(work_session_)) {
     return;
   }
 
   // Project the list of active types (i.e., types in the routing
@@ skipping 17 matching lines @@
     ModelSafeGroup group = worker->GetModelSafeGroup();
     // Skip workers whose group isn't active.
     if (active_groups.find(group) == active_groups.end()) {
       VLOG(2) << "Skipping worker for group "
               << ModelSafeGroupToString(group);
       continue;
     }
 
     sessions::StatusController* status = work_session_->status_controller();
     sessions::ScopedModelSafeGroupRestriction r(status, group);
-    scoped_ptr<Callback0::Type> c(NewCallback(this,
-        &ModelChangingSyncerCommand::StartChangingModel));
-    worker->DoWorkAndWaitUntilDone(c.get());
+    WorkCallback c = base::Bind(
+        &ModelChangingSyncerCommand::StartChangingModel,
+        // We wait until the callback is executed. So it is safe to use
+        // unretained.
+        base::Unretained(this));
+
+    // TODO(lipalani): Check the return value for an unrecoverable error.
+    ignore_result(worker->DoWorkAndWaitUntilDone(c));
+
   }
 }
 
 bool ModelChangingSyncerCommand::ModelNeutralExecuteImpl(
     sessions::SyncSession* session) {
   return true;
 }
 
 }  // namespace browser_sync