Oilpan: DatabaseThread::m_thread should not get destructed during sweeping

Source/modules/webdatabase/DatabaseContext.cpp

Index: Source/modules/webdatabase/DatabaseContext.cpp
diff --git a/Source/modules/webdatabase/DatabaseContext.cpp b/Source/modules/webdatabase/DatabaseContext.cpp
index b327f4c395b29d23963d714de3ca851644af63f4..2cfd3e48e5c024cde2c47001eb351a7af864b61f 100644
--- a/Source/modules/webdatabase/DatabaseContext.cpp
+++ b/Source/modules/webdatabase/DatabaseContext.cpp
@@ -183,10 +183,9 @@ void DatabaseContext::stopDatabases()
     // DatabaseThread.
 
     if (databaseThreadAvailable()) {
-        TaskSynchronizer sync;
-        m_databaseThread->requestTermination(&sync);
         m_hasRequestedTermination = true;
-        sync.waitForTaskCompletion();
+        // This blocks until the database thread finishes the cleanup task.
+        m_databaseThread->terminate();
     }
 }