components/webdata: Cleanup callback usage in WebDatabaseService.

components/webdata/common/web_data_service_base.cc

 // Copyright (c) 2012 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 "components/webdata/common/web_data_service_base.h"
 
 #include "base/bind.h"
 #include "base/message_loop.h"
 #include "base/stl_util.h"
 #include "base/threading/thread.h"
@@ skipping 44 matching lines @@
   wdbs_->CancelRequest(h);
 }
 
 bool WebDataServiceBase::IsDatabaseLoaded() {
   if (!wdbs_.get())
     return false;
   return wdbs_->db_loaded();
 }
 
 void WebDataServiceBase::RegisterDBLoadedCallback(
-    const base::Callback<void(void)>& callback) {
+    const DBLoadedCallback& callback) {
   if (!wdbs_.get())
     return;
   wdbs_->RegisterDBLoadedCallback(callback);
 }
 
 WebDatabase* WebDataServiceBase::GetDatabase() {
   if (!wdbs_.get())
     return NULL;
   return wdbs_->GetDatabaseOnDB();
 }
 
 WebDataServiceBase::~WebDataServiceBase() {
 }