Add tests for the XPC client.

chrome/browser/notifications/alert_dispatcher.h

+// Copyright 2016 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_BROWSER_NOTIFICATIONS_ALERT_DISPATCHER_H_
+#define CHROME_BROWSER_NOTIFICATIONS_ALERT_DISPATCHER_H_
+
+#import <Foundation/Foundation.h>
+
+// Interface to communicate with the Alert XPC service.
+@protocol AlertDispatcher<NSObject>
+
+// Deliver a notification to the XPC service to be displayed as an alert.
+- (void)dispatchNotification:(NSDictionary*)data;
+
+// Close a notification for a given |notificationId| and |profileId|.
+- (void)closeNotificationWithId:(NSString*)notificationId
+                  withProfileId:(NSString*)profileId;
+
+// Close all notifications.
+- (void)closeAllNotifications;
+
+@end
+
+#endif  // CHROME_BROWSER_NOTIFICATIONS_ALERT_DISPATCHER_H_