Expose ClientSession details to Host Extensions

remoting/host/client_session_details.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 REMOTING_HOST_CLIENT_SESSION_DETAILS_H_
+#define REMOTING_HOST_CLIENT_SESSION_DETAILS_H_
+
+#include <cstdint>
+
+namespace remoting {
+
+// Provides a selected set of state information about a ClientSession to
+// HostExtensions.
+class ClientSessionDetails {
+ public:
+  virtual ~ClientSessionDetails() {}
+
+  // Returns the id of the current desktop session being remoted.  If no session
+  // exists, UINT32_MAX is returned.
+  // Note: The return value should never be cached as it can change.
+  virtual uint32_t desktop_session_id() const = 0;
+};
+
+}  // namespace remoting
+
+#endif  // REMOTING_HOST_CLIENT_SESSION_DETAILS_H_