Revert of [Sync] Erase sync DB when corrupted

sync/syncable/directory.h

Index: sync/syncable/directory.h
diff --git a/sync/syncable/directory.h b/sync/syncable/directory.h
index 4f45cdfe18bf0e0e53e9d1df3b2b27283833e52c..7f6ae0e6343414178ef7b4f452206a089ef532c6 100644
--- a/sync/syncable/directory.h
+++ b/sync/syncable/directory.h
@@ -533,7 +533,6 @@
                            TakeSnapshotGetsOnlyDirtyHandlesTest);
   FRIEND_TEST_ALL_PREFIXES(SyncableDirectoryTest,
                            TakeSnapshotGetsMetahandlesToPurge);
-  FRIEND_TEST_ALL_PREFIXES(SyncableDirectoryTest, CatastrophicError);
 
   // You'll notice that some of the methods below are private overloads of the
   // public ones declared above. The general pattern is that the public overload
@@ -623,10 +622,6 @@
                             ModelType type,
                             std::vector<int64>* result);
 
-  // Invoked by DirectoryBackingStore when a catastrophic database error is
-  // detected.
-  void OnCatastrophicError();
-
   // Returns true if the initial sync for |type| has completed.
   bool InitialSyncEndedForType(BaseTransaction* trans, ModelType type);
 
@@ -658,8 +653,6 @@
   // are deleted in native models as well.
   scoped_ptr<DeleteJournal> delete_journal_;
 
-  base::WeakPtrFactory<Directory> weak_ptr_factory_;
-
   DISALLOW_COPY_AND_ASSIGN(Directory);
 };