Revert 179302

ui/app_list/signin_delegate.h

-// Copyright 2013 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 UI_APP_LIST_SIGNIN_DELEGATE_H_
-#define UI_APP_LIST_SIGNIN_DELEGATE_H_
-
-#include "base/basictypes.h"
-#include "base/observer_list.h"
-#include "ui/app_list/app_list_export.h"
-
-namespace content {
-class BrowserContext;
-class WebContents;
-}
-
-namespace app_list {
-
-class SigninDelegateObserver;
-
-class APP_LIST_EXPORT SigninDelegate {
- public:
-  SigninDelegate();
-  virtual ~SigninDelegate();
-
-  virtual bool NeedSignin() = 0;
-  virtual content::WebContents* PrepareForSignin() = 0;
-
-  void AddObserver(SigninDelegateObserver* observer);
-  void RemoveObserver(SigninDelegateObserver* observer);
-
- protected:
-  void NotifySigninSuccess();
-
- private:
-  ObserverList<SigninDelegateObserver, true> observers_;
-
-  DISALLOW_COPY_AND_ASSIGN(SigninDelegate);
-};
-
-}  // namespace app_list
-
-#endif  // UI_APP_LIST_SIGNIN_DELEGATE_H_