Add CompositeMachMessageServer and its test

util/mach/child_port_server.h

 // Copyright 2014 The Crashpad Authors. All rights reserved.
 //
 // Licensed under the Apache License, Version 2.0 (the "License");
 // you may not use this file except in compliance with the License.
 // You may obtain a copy of the License at
 //
 //     http://www.apache.org/licenses/LICENSE-2.0
 //
 // Unless required by applicable law or agreed to in writing, software
 // distributed under the License is distributed on an "AS IS" BASIS,
@@ skipping 44 matching lines @@
   //!
   //! \param[in] interface The interface to dispatch requests to. Weak.
   explicit ChildPortServer(Interface* interface);
 
   // MachMessageServer::Interface:
 
   bool MachMessageServerFunction(const mach_msg_header_t* in_header,
                                  mach_msg_header_t* out_header,
                                  bool* destroy_complex_request) override;
 
+  std::set<mach_msg_id_t> MachMessageServerRequestIDs() override;
+
   mach_msg_size_t MachMessageServerRequestSize() override;
   mach_msg_size_t MachMessageServerReplySize() override;
 
  private:
   Interface* interface_;  // weak
 
   DISALLOW_COPY_AND_ASSIGN(ChildPortServer);
 };
 
 }  // namespace crashpad
 
 #endif  // CRASHPAD_UTIL_MACH_CHILD_PORT_SERVER_H_