Add return values to SyncerCommand

chrome/browser/sync/engine/verify_updates_command.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_VERIFY_UPDATES_COMMAND_H_
 #define CHROME_BROWSER_SYNC_ENGINE_VERIFY_UPDATES_COMMAND_H_
 #pragma once
 
 #include "base/basictypes.h"
 #include "base/compiler_specific.h"
@@ skipping 12 matching lines @@
 // noted in the SyncSession after this command is executed.
 class VerifyUpdatesCommand : public ModelChangingSyncerCommand {
  public:
   VerifyUpdatesCommand();
   virtual ~VerifyUpdatesCommand();
 
  protected:
   // ModelChangingSyncerCommand implementation.
   virtual std::set<ModelSafeGroup> GetGroupsToChange(
       const sessions::SyncSession& session) const OVERRIDE;
-  virtual void ModelChangingExecuteImpl(
+  virtual SyncerError ModelChangingExecuteImpl(
       sessions::SyncSession* session) OVERRIDE;
 
  private:
   struct VerifyUpdateResult {
     VerifyResult value;
     ModelSafeGroup placement;
   };
   VerifyUpdateResult VerifyUpdate(syncable::WriteTransaction* trans,
                                   const SyncEntity& entry,
                                   const ModelSafeRoutingInfo& routes);
   DISALLOW_COPY_AND_ASSIGN(VerifyUpdatesCommand);
 };
 
 }  // namespace browser_sync
 
 #endif  // CHROME_BROWSER_SYNC_ENGINE_VERIFY_UPDATES_COMMAND_H_