[Sync] Remove backend unrecoverable error handler

sync/syncable/directory.h

 // Copyright 2013 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_SYNCABLE_DIRECTORY_H_
 #define SYNC_SYNCABLE_DIRECTORY_H_
 
 #include <deque>
 #include <set>
 #include <string>
@@ skipping 230 matching lines @@
     // The delegate for directory change events.  Must not be NULL.
     DirectoryChangeDelegate* const delegate;
 
     // The transaction observer.
     const WeakHandle<TransactionObserver> transaction_observer;
   };
 
   // Does not take ownership of |encryptor|.
   // |report_unrecoverable_error_function| may be NULL.
   // Takes ownership of |store|.
-  Directory(DirectoryBackingStore* store,
-            UnrecoverableErrorHandler* unrecoverable_error_handler,
-            const base::Closure& report_unrecoverable_error_function,
-            NigoriHandler* nigori_handler,
-            Cryptographer* cryptographer);
+  Directory(
+      DirectoryBackingStore* store,
+      const WeakHandle<UnrecoverableErrorHandler>& unrecoverable_error_handler,
+      const base::Closure& report_unrecoverable_error_function,
+      NigoriHandler* nigori_handler,
+      Cryptographer* cryptographer);
   virtual ~Directory();
 
   // Does not take ownership of |delegate|, which must not be NULL.
   // Starts sending events to |delegate| if the returned result is
   // OPENED.  Note that events to |delegate| may be sent from *any*
   // thread.  |transaction_observer| must be initialized.
   DirOpenResult Open(const std::string& name,
                      DirectoryChangeDelegate* delegate,
                      const WeakHandle<TransactionObserver>&
                          transaction_observer);
@@ skipping 363 matching lines @@
   // Returns true if the directory had encountered an unrecoverable error.
   // Note: Any function in |Directory| that can be called without holding a
   // transaction need to check if the Directory already has an unrecoverable
   // error on it.
   bool unrecoverable_error_set(const BaseTransaction* trans) const;
 
   Kernel* kernel_;
 
   scoped_ptr<DirectoryBackingStore> store_;
 
-  UnrecoverableErrorHandler* const unrecoverable_error_handler_;
+  const WeakHandle<UnrecoverableErrorHandler> unrecoverable_error_handler_;
   base::Closure report_unrecoverable_error_function_;
   bool unrecoverable_error_set_;
 
   // Not owned.
   NigoriHandler* const nigori_handler_;
   Cryptographer* const cryptographer_;
 
   InvariantCheckLevel invariant_check_level_;
 
   // Maintain deleted entries not in |kernel_| until it's verified that they
   // are deleted in native models as well.
   scoped_ptr<DeleteJournal> delete_journal_;
 
   base::WeakPtrFactory<Directory> weak_ptr_factory_;
 
   DISALLOW_COPY_AND_ASSIGN(Directory);
 };
 
 }  // namespace syncable
 }  // namespace syncer
 
 #endif // SYNC_SYNCABLE_DIRECTORY_H_