Eliminated the last few uses of MessageLoop::QuitTask in chrome/

chrome/browser/history/history_unittest.cc

 // Copyright (c) 2011 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.
 
 // History unit tests come in two flavors:
 //
 // 1. The more complicated style is that the unit test creates a full history
 //    service. This spawns a background thread for the history backend, and
 //    all communication is asynchronous. This is useful for testing more
 //    complicated things or end-to-end behavior.
@@ skipping 150 matching lines @@
   }
 
   virtual void TearDown() {
     DeleteBackend();
 
     if (history_service_)
       CleanupHistoryService();
 
     // Make sure we don't have any event pending that could disrupt the next
     // test.
-    MessageLoop::current()->PostTask(FROM_HERE, new MessageLoop::QuitTask);
+    MessageLoop::current()->PostTask(FROM_HERE, MessageLoop::QuitClosure());
     MessageLoop::current()->Run();
   }
 
   void CleanupHistoryService() {
     DCHECK(history_service_.get());
 
     history_service_->NotifyRenderProcessHostDestruction(0);
-    history_service_->SetOnBackendDestroyTask(new MessageLoop::QuitTask);
+    history_service_->SetOnBackendDestroyTask(MessageLoop::QuitClosure());
     history_service_->Cleanup();
     history_service_ = NULL;
 
     // Wait for the backend class to terminate before deleting the files and
     // moving to the next test. Note: if this never terminates, somebody is
     // probably leaking a reference to the history backend, so it never calls
     // our destroy task.
     MessageLoop::current()->Run();
   }
 
@@ skipping 768 matching lines @@
   history_service_ = history;
   history->ScheduleDBTask(task.get(), &request_consumer);
   request_consumer.CancelAllRequests();
   CleanupHistoryService();
   // WARNING: history has now been deleted.
   history = NULL;
   ASSERT_FALSE(task->done_invoked);
 }
 
 }  // namespace history