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/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"
@@ skipping 30 matching lines @@
       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());
+
+    if (session->unrecoverable_error()) {

[akalin, 2011/10/21 22:18:27]

Why not just make the (optional) unrecoverable error a return value of
DoWorkAndWaitUntilDone?

Then, why not make that error a return value of ExecuteImpl and have the syncer
check it, then propagate up to the SyncScheduler, etc.?

[lipalani1, 2011/10/21 23:40:03]

Agreed
On 2011/10/21 22:18:27, akalin wrote:

+      // We are back on the syncer thread. Now use the delegate to send the
+      // error.
+      DCHECK(session->unrecoverable_error_info());
+      session->delegate()->OnUnrecoverableError(
+          session->unrecoverable_error_info()->location,
+          session->unrecoverable_error_info()->message);
+      break;
+    }
   }
 }
 
 bool ModelChangingSyncerCommand::ModelNeutralExecuteImpl(
     sessions::SyncSession* session) {
   return true;
 }
 
 }  // namespace browser_sync