Delete callbacks after use in canned browsing data helpers.

chrome/browser/browsing_data_database_helper.cc

 // Copyright (c) 2010 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 "chrome/browser/browsing_data_database_helper.h"
 
 #include "base/callback.h"
 #include "base/file_util.h"
 #include "base/message_loop.h"
 #include "base/utf_string_conversions.h"
@@ skipping 132 matching lines @@
         base::Time()));
 }
 
 void CannedBrowsingDataDatabaseHelper::Reset() {
   database_info_.clear();
 }
 
 void CannedBrowsingDataDatabaseHelper::StartFetching(
     Callback1<const std::vector<DatabaseInfo>& >::Type* callback) {
   callback->Run(database_info_);
+  delete callback;
 }