Rename DatabaseTaskSynchronizer to TaskSynchronizer and move it to platform/

Source/modules/webdatabase/DatabaseThread.h

Index: Source/modules/webdatabase/DatabaseThread.h
diff --git a/Source/modules/webdatabase/DatabaseThread.h b/Source/modules/webdatabase/DatabaseThread.h
index 3ef0b00457c3689275435fe5911ea17cc59ba38d..d6ea641cb6aeff25a2f8cb9dfae1edf2a54b89e9 100644
--- a/Source/modules/webdatabase/DatabaseThread.h
+++ b/Source/modules/webdatabase/DatabaseThread.h
@@ -44,7 +44,7 @@ namespace WebCore {
 
 class DatabaseBackend;
 class DatabaseTask;
-class DatabaseTaskSynchronizer;
+class TaskSynchronizer;
 class Document;
 class MessageLoopInterruptor;
 class PendingGCRunner;
@@ -57,8 +57,8 @@ public:
     ~DatabaseThread();
 
     void start();
-    void requestTermination(DatabaseTaskSynchronizer* cleanupSync);
-    bool terminationRequested(DatabaseTaskSynchronizer* taskSynchronizer = 0) const;
+    void requestTermination(TaskSynchronizer* cleanupSync);
+    bool terminationRequested(TaskSynchronizer* = 0) const;
 
     void scheduleTask(PassOwnPtr<DatabaseTask>);
 
@@ -87,7 +87,7 @@ private:
 
     OwnPtr<SQLTransactionClient> m_transactionClient;
     OwnPtr<SQLTransactionCoordinator> m_transactionCoordinator;
-    DatabaseTaskSynchronizer* m_cleanupSync;
+    TaskSynchronizer* m_cleanupSync;
 
     mutable Mutex m_terminationRequestedMutex;
     bool m_terminationRequested;