Add an XPC implementation of sandbox::MessageServer.

sandbox/mac/xpc_message_server.h

Index: sandbox/mac/xpc_message_server.h
diff --git a/sandbox/mac/xpc_message_server.h b/sandbox/mac/xpc_message_server.h
new file mode 100644
index 0000000000000000000000000000000000000000..99edb26abfd0ec2c6d93610e0ab205b09080fe6f
--- /dev/null
+++ b/sandbox/mac/xpc_message_server.h
@@ -0,0 +1,62 @@
+// 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 SANDBOX_MAC_XPC_MESSAGE_SERVER_H_
+#define SANDBOX_MAC_XPC_MESSAGE_SERVER_H_
+
+#include "base/mac/scoped_mach_port.h"
+#include "base/memory/scoped_ptr.h"
+#include "sandbox/mac/message_server.h"
+#include "sandbox/mac/xpc.h"
+#include "sandbox/sandbox_export.h"
+
+namespace sandbox {
+
+class DispatchSourceMach;
+
+// An implementation of MessageServer that uses XPC pipes to read and write XPC
+// messages from a Mach port.
+class SANDBOX_EXPORT XPCMessageServer : public MessageServer {
+ public:
+  // Creates a new XPC message server that will send messages to |demuxer|
+  // for handling. If the |server_receive_right| is non-NULL, this class will
+  // take ownership of the port and it will be used to receive messages.
+  // Otherwise the server will create a new receive right on which to listen.
+  XPCMessageServer(MessageDemuxer* demuxer,
+                   mach_port_t server_receive_right);
+  virtual ~XPCMessageServer();
+
+  // MessageServer:
+  virtual bool Initialize() OVERRIDE;
+  virtual pid_t GetMessageSenderPID(IPCMessage request) OVERRIDE;
+  virtual IPCMessage CreateReply(IPCMessage request) OVERRIDE;
+  virtual bool SendReply(IPCMessage reply) OVERRIDE;
+  virtual void ForwardMessage(IPCMessage request,
+                              mach_port_t destination) OVERRIDE;
+  // Creates an error reply message with a field "error" set to |error_code|.
+  virtual void RejectMessage(IPCMessage request, int error_code) OVERRIDE;
+  virtual mach_port_t GetServerPort() const OVERRIDE;
+
+ private:
+  // Reads a message from the XPC pipe.
+  void ReceiveMessage();
+
+  // The demuxer delegate. Weak.
+  MessageDemuxer* demuxer_;
+
+  // The Mach port on which the server is receiving requests.
+  base::mac::ScopedMachReceiveRight server_port_;
+
+  // MACH_RECV dispatch source that handles the |server_port_|.
+  scoped_ptr<DispatchSourceMach> dispatch_source_;
+
+  // The reply message, if one has been created.
+  xpc_object_t reply_message_;
+
+  DISALLOW_COPY_AND_ASSIGN(XPCMessageServer);
+};
+
+}  // namespace sandbox
+
+#endif  // SANDBOX_MAC_XPC_MESSAGE_SERVER_H_