Make DatabaseTask inherit from WebTask

Source/modules/webdatabase/DatabaseTask.cpp

 /*
  * Copyright (C) 2007, 2008, 2013 Apple Inc. All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions
  * are met:
  *
  * 1.  Redistributions of source code must retain the above copyright
  *     notice, this list of conditions and the following disclaimer.
  * 2.  Redistributions in binary form must reproduce the above copyright
@@ skipping 55 matching lines @@
 {
 }
 
 DatabaseTask::~DatabaseTask()
 {
 #if !LOG_DISABLED
     ASSERT(m_complete || !m_synchronizer);
 #endif
 }
 
-void DatabaseTask::performTask()
+void DatabaseTask::run()
 {
     // Database tasks are meant to be used only once, so make sure this one hasn't been performed before.
 #if !LOG_DISABLED
     ASSERT(!m_complete);
 #endif
 
     LOG(StorageAPI, "Performing %s %p\n", debugTaskName(), this);
 
     m_database->resetAuthorizer();
     doPerformTask();
@@ skipping 107 matching lines @@
 }
 
 #if !LOG_DISABLED
 const char* DatabaseBackend::DatabaseTableNamesTask::debugTaskName() const
 {
     return "DatabaseTableNamesTask";
 }
 #endif
 
 } // namespace WebCore