Refactor notifications of chrome/browser/webdata

chrome/test/base/thread_observer_helper.h

-// 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.
-
-#ifndef CHROME_TEST_BASE_THREAD_OBSERVER_HELPER_H_
-#define CHROME_TEST_BASE_THREAD_OBSERVER_HELPER_H_
-
-#include "base/bind.h"
-#include "base/memory/ref_counted.h"
-#include "base/sequenced_task_runner_helpers.h"
-#include "base/synchronization/waitable_event.h"
-#include "content/public/browser/browser_thread.h"
-#include "content/public/browser/notification_registrar.h"
-#include "content/public/test/mock_notification_observer.h"
-
-// Helper class to add and remove observers on a non-UI thread from
-// the UI thread.
-template <class T, typename Traits>
-class ThreadObserverHelper : public base::RefCountedThreadSafe<T, Traits> {
- public:
-  explicit ThreadObserverHelper(content::BrowserThread::ID id)
-      : id_(id), done_event_(false, false) {}
-
-  void Init() {
-    using content::BrowserThread;
-    DCHECK(BrowserThread::CurrentlyOn(BrowserThread::UI));
-    BrowserThread::PostTask(
-        id_,
-        FROM_HERE,
-        base::Bind(&ThreadObserverHelper::RegisterObserversTask, this));
-    done_event_.Wait();
-  }
-
-  virtual ~ThreadObserverHelper() {
-    DCHECK(content::BrowserThread::CurrentlyOn(id_));
-    registrar_.RemoveAll();
-  }
-
-  content::MockNotificationObserver* observer() {
-    return &observer_;
-  }
-
- protected:
-  friend class base::RefCountedThreadSafe<T>;
-
-  virtual void RegisterObservers() = 0;
-
-  content::NotificationRegistrar registrar_;
-  content::MockNotificationObserver observer_;
-
- private:
-  void RegisterObserversTask() {
-    DCHECK(content::BrowserThread::CurrentlyOn(id_));
-    RegisterObservers();
-    done_event_.Signal();
-  }
-
-  content::BrowserThread::ID id_;
-  base::WaitableEvent done_event_;
-};
-
-class DBThreadObserverHelper;
-typedef ThreadObserverHelper<
-    DBThreadObserverHelper,
-    content::BrowserThread::DeleteOnDBThread> DBThreadObserverHelperBase;
-
-class DBThreadObserverHelper : public DBThreadObserverHelperBase {
- public:
-  DBThreadObserverHelper() :
-      DBThreadObserverHelperBase(content::BrowserThread::DB) {}
-
- protected:
-  friend struct content::BrowserThread::DeleteOnThread<
-      content::BrowserThread::DB>;
-  friend class base::DeleteHelper<DBThreadObserverHelper>;
-
-  virtual ~DBThreadObserverHelper() {}
-};
-
-#endif  // CHROME_TEST_BASE_THREAD_OBSERVER_HELPER_H_