[EasyUnlock] Port Connection class to native code.

components/proximity_auth/connection_observer.h

+// Copyright 2014 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 COMPONENTS_PROXIMITY_AUTH_CONNECTION_OBSERVER_H
+#define COMPONENTS_PROXIMITY_AUTH_CONNECTION_OBSERVER_H
+
+#include "components/proximity_auth/connection.h"
+
+namespace proximity_auth {
+
+class WireMessage;
+
+// An interface for observing events that happen on a Connection.
+class ConnectionObserver {
+ public:
+  // Called when the |connection|'s status changes from |old_status| to
+  // |new_status|.
+  virtual void OnConnectionStatusChanged(const Connection& connection,
+                                         Connection::Status old_status,
+                                         Connection::Status new_status) = 0;
+
+  // Called when a |message| is received from a remote device over the
+  // |connection|.
+  virtual void OnMessageReceived(const Connection& connection,
+                                 const WireMessage& message) = 0;
+
+  // Called after a |message| is sent to the remote device over the
+  // |connection|. |success| is |true| iff the message is sent successfully.
+  virtual void OnSendCompleted(const Connection& connection,
+                               const WireMessage& message,
+                               bool success) = 0;
+};
+
+}  // namespace proximity_auth
+
+#endif  // COMPONENTS_PROXIMITY_AUTH_CONNECTION_OBSERVER_H