Revert of [sql] Use memory-mapped I/O for sql::Connection.

sync/syncable/directory_backing_store.cc

 // 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.
 
 #include "sync/syncable/directory_backing_store.h"
 
 #include "build/build_config.h"
 
 #include <limits>
 
@@ skipping 1672 matching lines @@
 bool DirectoryBackingStore::needs_column_refresh() const {
   return needs_column_refresh_;
 }
 
 void DirectoryBackingStore::ResetAndCreateConnection() {
   db_.reset(new sql::Connection());
   db_->set_histogram_tag("SyncDirectory");
   db_->set_exclusive_locking();
   db_->set_cache_size(32);
   db_->set_page_size(database_page_size_);
-
-  // TODO(shess): Sync corruption tests interact poorly with mmap, disable for
-  // now.  http://crbug.com/533682
-  db_->set_mmap_disabled();
   if (!catastrophic_error_handler_.is_null())
     SetCatastrophicErrorHandler(catastrophic_error_handler_);
 }
 
 void DirectoryBackingStore::SetCatastrophicErrorHandler(
     const base::Closure& catastrophic_error_handler) {
   DCHECK(CalledOnValidThread());
   DCHECK(!catastrophic_error_handler.is_null());
   catastrophic_error_handler_ = catastrophic_error_handler;
   sql::Connection::ErrorCallback error_callback =
       base::Bind(&OnSqliteError, catastrophic_error_handler_);
   db_->set_error_callback(error_callback);
 }
 
 }  // namespace syncable
 }  // namespace syncer