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

chrome/browser/sync/engine/apply_updates_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/apply_updates_command.h"
 
 #include "base/location.h"
 #include "chrome/browser/sync/engine/update_applicator.h"
 #include "chrome/browser/sync/sessions/sync_session.h"
 #include "chrome/browser/sync/syncable/directory_manager.h"
@@ skipping 16 matching lines @@
   syncable::WriteTransaction trans(FROM_HERE, syncable::SYNCER, dir);
   syncable::Directory::UnappliedUpdateMetaHandles handles;
   dir->GetUnappliedUpdateMetaHandles(&trans, &handles);
 
   UpdateApplicator applicator(
       session->context()->resolver(),
       session->context()->directory_manager()->GetCryptographer(&trans),
       handles.begin(), handles.end(), session->routing_info(),
       session->status_controller()->group_restriction());
   while (applicator.AttemptOneApplication(&trans)) {}
+
+  if (applicator.failed_update()) {
+    // TODO(lipalani): Pipe in the failed line number from the syncable layer.
+
+    // We could be in any thread here. So set the unrecoverable error in.
+    // session. ModelChangingSyncerCommand object will send it on the right
+    // thread.
+    session->SetUnrecoverableError(FROM_HERE, "Failed to apply update.",
+        &trans);
+    return;
+  }
+
   applicator.SaveProgressIntoSessionState(
       session->status_controller()->mutable_conflict_progress(),
       session->status_controller()->mutable_update_progress());
 
   // This might be the first time we've fully completed a sync cycle, for
   // some subset of the currently synced datatypes.
   sessions::StatusController* status(session->status_controller());
   if (status->ServerSaysNothingMoreToDownload()) {
     syncable::ScopedDirLookup dir(session->context()->directory_manager(),
                                   session->context()->account_name());
     if (!dir.good()) {
       LOG(ERROR) << "Scoped dir lookup failed!";
       return;
     }
 
     for (int i = syncable::FIRST_REAL_MODEL_TYPE;
          i < syncable::MODEL_TYPE_COUNT; ++i) {
       syncable::ModelType model_type = syncable::ModelTypeFromInt(i);
       if (status->updates_request_types()[i]) {
         // This gets persisted to the directory's backing store.
         dir->set_initial_sync_ended_for_type(model_type, true);
       }
     }
   }
 }
 
 }  // namespace browser_sync