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

chrome/browser/sync/engine/model_safe_worker.h

 // 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.
 
 #ifndef CHROME_BROWSER_SYNC_ENGINE_MODEL_SAFE_WORKER_H_
 #define CHROME_BROWSER_SYNC_ENGINE_MODEL_SAFE_WORKER_H_
 #pragma once
 
 #include <map>
 #include <string>
 #include <vector>
 
+#include "base/callback.h"
 #include "base/callback_old.h"
 #include "base/memory/ref_counted.h"
 #include "chrome/browser/sync/syncable/model_type.h"
+#include "chrome/browser/sync/util/unrecoverable_error_info.h"
 
 namespace base {
 class DictionaryValue;
 }  // namespace
 
 namespace browser_sync {
 
+typedef base::Callback<UnrecoverableErrorInfo(void)> WorkCallback;
+
 enum ModelSafeGroup {
   GROUP_PASSIVE = 0,   // Models that are just "passively" being synced; e.g.
                        // changes to these models don't need to be pushed to a
                        // native model.
   GROUP_UI,            // Models that live on UI thread and are being synced.
   GROUP_DB,            // Models that live on DB thread and are being synced.
   GROUP_FILE,          // Models that live on FILE thread and are being synced.
   GROUP_HISTORY,       // Models that live on history thread and are being
                        // synced.
   GROUP_PASSWORD,      // Models that live on the password thread and are
@@ skipping 12 matching lines @@
 // cause an embedding application model to fall out of sync with the
 // syncable::Directory due to a race.
 class ModelSafeWorker : public base::RefCountedThreadSafe<ModelSafeWorker> {
  public:
   ModelSafeWorker();
   virtual ~ModelSafeWorker();
 
   // Any time the Syncer performs model modifications (e.g employing a
   // WriteTransaction), it should be done by this method to ensure it is done
   // from a model-safe thread.
-  virtual void DoWorkAndWaitUntilDone(Callback0::Type* work);
+  virtual UnrecoverableErrorInfo DoWorkAndWaitUntilDone(
+      const WorkCallback& work);
 
   virtual ModelSafeGroup GetModelSafeGroup();
 
  private:
   friend class base::RefCountedThreadSafe<ModelSafeWorker>;
 
   DISALLOW_COPY_AND_ASSIGN(ModelSafeWorker);
 };
 
 // A map that details which ModelSafeGroup each syncable::ModelType
@@ skipping 36 matching lines @@
   virtual void GetModelSafeRoutingInfo(ModelSafeRoutingInfo* out) = 0;
  protected:
   virtual ~ModelSafeWorkerRegistrar() {}
  private:
   DISALLOW_COPY_AND_ASSIGN(ModelSafeWorkerRegistrar);
 };
 
 }  // namespace browser_sync
 
 #endif  // CHROME_BROWSER_SYNC_ENGINE_MODEL_SAFE_WORKER_H_