Moving host status events monitoring to a separate interface (HostStatusMonitor).

remoting/host/host_status_monitor.h

+// Copyright (c) 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 REMOTING_HOST_HOST_STATUS_MONITOR_H_
+#define REMOTING_HOST_HOST_STATUS_MONITOR_H_
+
+namespace remoting {
+
+class HostStatusObserver;
+
+// Interface for registering host status observers.
+class HostStatusMonitor {
+ public:
+  virtual ~HostStatusMonitor() {}
+
+  // Add/Remove |observer| to/from the list of status observers.
+  virtual void AddStatusObserver(HostStatusObserver* observer) = 0;
+  virtual void RemoveStatusObserver(HostStatusObserver* observer) = 0;
+};
+
+}  // namespace remoting
+
+#endif  // REMOTING_HOST_HOST_STATUS_MONITOR_H_