Fix simple_database_system.cc to correctly support temp DB files....

webkit/tools/test_shell/simple_database_system.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 "webkit/tools/test_shell/simple_database_system.h"
 
 #if defined(USE_SYSTEM_SQLITE)
 #include <sqlite3.h>
 #else
 #include "third_party/sqlite/preprocessed/sqlite3.h"
@@ skipping 174 matching lines @@
 
   AutoLock file_names_auto_lock(file_names_lock_);
   file_names_[vfs_file_name] = file_name;
   file_names_[vfs_file_name + ASCIIToUTF16("-journal")] =
       FilePath::FromWStringHack(file_name.ToWStringHack() +
                                 ASCIIToWide("-journal"));
 }
 
 FilePath SimpleDatabaseSystem::GetFullFilePathForVfsFile(
     const string16& vfs_file_name) {
+  if (vfs_file_name.empty())  // temp file, used for vacuuming
+    return FilePath();
+
   AutoLock file_names_auto_lock(file_names_lock_);
   DCHECK(file_names_.find(vfs_file_name) != file_names_.end());
   return file_names_[vfs_file_name];
 }