FBTF: Remove unneeded headers from base/ (part 2)

chrome/browser/sync/glue/database_model_worker.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 "chrome/browser/sync/glue/database_model_worker.h"
 
+#include "base/waitable_event.h"
 #include "chrome/browser/chrome_thread.h"
 
 using base::WaitableEvent;
 
 namespace browser_sync {
 
 void DatabaseModelWorker::DoWorkAndWaitUntilDone(Callback0::Type* work) {
   if (ChromeThread::CurrentlyOn(ChromeThread::DB)) {
     DLOG(WARNING) << "DoWorkAndWaitUntilDone called from the DB thread.";
     work->Run();
@@ skipping 14 matching lines @@
   DCHECK(ChromeThread::CurrentlyOn(ChromeThread::DB));
   work->Run();
   done->Signal();
 }
 
 bool DatabaseModelWorker::CurrentThreadIsWorkThread() {
   return ChromeThread::CurrentlyOn(ChromeThread::DB);
 }
 
 }  // namespace browser_sync