[win] Add signin support for the app launcher.

ui/app_list/signin_delegate_observer.h

Index: ui/app_list/signin_delegate_observer.h
diff --git a/ui/app_list/signin_delegate_observer.h b/ui/app_list/signin_delegate_observer.h
new file mode 100644
index 0000000000000000000000000000000000000000..47c499260ef7b0e9cd03f7c404495dab0a4d0753
--- /dev/null
+++ b/ui/app_list/signin_delegate_observer.h
@@ -0,0 +1,24 @@
+// 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_OBSERVER_H_
+#define UI_APP_LIST_SIGNIN_DELEGATE_OBSERVER_H_
+
+#include "ui/app_list/app_list_export.h"
+
+namespace app_list {
+
+// Abstract interface to allow handling app list signin success.
+class APP_LIST_EXPORT SigninDelegateObserver {
+ public:
+  // Called by the SigninDelegate when signin has successfully completed.
+  virtual void OnSigninSuccess() = 0;
+
+ protected:
+  virtual ~SigninDelegateObserver() {}
+};
+
+}  // namespace app_list
+
+#endif  // UI_APP_LIST_SIGNIN_DELEGATE_OBSERVER_H_