display: add support for IDisplayConfig 2.0

Change-Id: I7193697b95ea58c5661d3a8782c30ada3813a042
diff --git a/services/config/client_interface.h b/services/config/client_interface.h
new file mode 100644
index 0000000..faf772a
--- /dev/null
+++ b/services/config/client_interface.h
@@ -0,0 +1,49 @@
+/*
+* Copyright (c) 2020 The Linux Foundation. All rights reserved.
+*
+* Redistribution and use in source and binary forms, with or without
+* modification, are permitted provided that the following conditions are
+* met:
+*    * Redistributions of source code must retain the above copyright
+*      notice, this list of conditions and the following disclaimer.
+*    * Redistributions in binary form must reproduce the above
+*      copyright notice, this list of conditions and the following
+*      disclaimer in the documentation and/or other materials provided
+*      with the distribution.
+*    * Neither the name of The Linux Foundation. nor the names of its
+*      contributors may be used to endorse or promote products derived
+*      from this software without specific prior written permission.
+*
+* THIS SOFTWARE IS PROVIDED "AS IS" AND ANY EXPRESS OR IMPLIED
+* WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
+* MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NON-INFRINGEMENT
+* ARE DISCLAIMED.  IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS
+* BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
+* CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
+* SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR
+* BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY,
+* WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE
+* OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN
+* IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+*/
+
+#ifndef __CLIENT_INTERFACE_H__
+#define __CLIENT_INTERFACE_H__
+
+#include "config_defs.h"
+
+namespace DisplayConfig {
+
+class ClientInterface : public ConfigInterface  {
+ public:
+  static int Create(std::string client_name, ConfigCallback *callback,
+                    ClientInterface **intf);
+  static void Destroy(ClientInterface *intf);
+
+ protected:
+  virtual ~ClientInterface() { }
+};
+
+}  // namespace DisplayConfig
+
+#endif  // __CLIENT_INTERFACE_H__