[Sync] Remove backend unrecoverable error handler

sync/internal_api/sync_manager_impl.h

 // Copyright 2012 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 SYNC_INTERNAL_API_SYNC_MANAGER_H_
 #define SYNC_INTERNAL_API_SYNC_MANAGER_H_
 
 #include <string>
 #include <vector>
 
@@ skipping 317 matching lines @@
   // These are for interacting with chrome://sync-internals.
   JsSyncManagerObserver js_sync_manager_observer_;
   JsMutationEventObserver js_mutation_event_observer_;
   JsSyncEncryptionHandlerObserver js_sync_encryption_handler_observer_;
 
   // This is for keeping track of client events to send to the server.
   DebugInfoEventListener debug_info_event_listener_;
 
   ProtocolEventBuffer protocol_event_buffer_;
 
-  scoped_ptr<UnrecoverableErrorHandler> unrecoverable_error_handler_;
   base::Closure report_unrecoverable_error_function_;
 
   // Sync's encryption handler. It tracks the set of encrypted types, manages
   // changing passphrases, and in general handles sync-specific interactions
   // with the cryptographer.
   scoped_ptr<SyncEncryptionHandlerImpl> sync_encryption_handler_;
 
   base::WeakPtrFactory<SyncManagerImpl> weak_ptr_factory_;
 
   DISALLOW_COPY_AND_ASSIGN(SyncManagerImpl);
 };
 
 }  // namespace syncer
 
 #endif  // SYNC_INTERNAL_API_SYNC_MANAGER_H_