Fix virtual/override/final usage in Source/modules/.

Source/modules/webdatabase/DatabaseTracker.cpp

Index: Source/modules/webdatabase/DatabaseTracker.cpp
diff --git a/Source/modules/webdatabase/DatabaseTracker.cpp b/Source/modules/webdatabase/DatabaseTracker.cpp
index b1206aeca2271edf114337c016fb6d4c31b81cb5..a5345ce08994362b083b82280cc39e854ba1caba 100644
--- a/Source/modules/webdatabase/DatabaseTracker.cpp
+++ b/Source/modules/webdatabase/DatabaseTracker.cpp
@@ -113,7 +113,7 @@ public:
         return adoptPtr(new NotifyDatabaseObserverOnCloseTask(database));
     }
 
-    virtual void performTask(ExecutionContext*) override
+    void performTask(ExecutionContext*) override
     {
         databaseClosed(m_database.get());
     }
@@ -200,7 +200,7 @@ public:
         return adoptPtr(new CloseOneDatabaseImmediatelyTask(originIdentifier, name, database));
     }
 
-    virtual void performTask(ExecutionContext*) override
+    void performTask(ExecutionContext*) override
     {
         DatabaseTracker::tracker().closeOneDatabaseImmediately(m_originIdentifier, m_name, m_database);
     }