Decouple Blimp transport output from BlimpConnections using MessagePort.

blimp/net/message_port_util.h

Index: blimp/net/message_port_util.h
diff --git a/blimp/net/message_port_util.h b/blimp/net/message_port_util.h
new file mode 100644
index 0000000000000000000000000000000000000000..1f18a4117b62efd180a6fc1cc43d69acc3605970
--- /dev/null
+++ b/blimp/net/message_port_util.h
@@ -0,0 +1,25 @@
+// 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 BLIMP_NET_MESSAGE_PORT_UTIL_H_
+#define BLIMP_NET_MESSAGE_PORT_UTIL_H_
+
+#include <memory>
+
+namespace net {
+class StreamSocket;
+}  // net
+
+namespace blimp {
+
+class MessagePort;
+
+// Constructs a MessagePort object that sends and receives packets using
+// |socket|.
+std::unique_ptr<MessagePort> CreateMessagePortForStreamSocket(
+    std::unique_ptr<net::StreamSocket> socket);
+
+}  // namespace blimp
+
+#endif  // BLIMP_NET_MESSAGE_PORT_UTIL_H_