[win] Add signin support for the app launcher.

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_