Add P2PDatagramSocket and P2PStreamSocket interfaces.

remoting/protocol/p2p_datagram_socket.h

Index: remoting/protocol/p2p_datagram_socket.h
diff --git a/remoting/protocol/p2p_datagram_socket.h b/remoting/protocol/p2p_datagram_socket.h
new file mode 100644
index 0000000000000000000000000000000000000000..9b7f7490b2d28c2acac23d35cfe5098ca07cac0e
--- /dev/null
+++ b/remoting/protocol/p2p_datagram_socket.h
@@ -0,0 +1,39 @@
+// Copyright 2015 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_PROTOCOL_P2P_DATAGRAM_SOCKET_H_
+#define REMOTING_PROTOCOL_P2P_DATAGRAM_SOCKET_H_
+
+#include "net/base/completion_callback.h"
+
+namespace net {
+class IOBuffer;
+}  // namespace net
+
+namespace remoting {
+namespace protocol {
+
+// Peer-to-peer socket with datagram semantics.
+class P2PDatagramSocket {
+ public:
+  virtual ~P2PDatagramSocket() {};
+
+  // Receives a packet, up to |buf_len| bytes, from the socket. The number of
+  // bytes read is returned, or an error is returned upon failure.
+  // ERR_IO_PENDING is returned if the operation could not be completed
+  // synchronously, in which case the result will be passed to the callback when
+  // available. If the operation is not completed immediately, the socket
+  // acquires a reference to the provided buffer until the callback is invoked
+  // or the socket is closed. If the socket is destroyed before the read
+  // completes, the callback will not be invoked.

[Wez, 2015/07/10 01:18:24]

What happens if a packet larger than |buf_len| is received? Is that an error? Or
will it be truncated? Or not returned at all?

[Sergey Ulanov, 2015/07/10 20:48:57]

Added a separate comment for Send().

[Wez, 2015/07/14 18:28:09]

That comment doesn't clarify the Recv() behaviour if an incoming packet exceeds
|buf_len| in size, though?

[Sergey Ulanov, 2015/07/14 21:07:54]

Done.

+  virtual int Recv(net::IOBuffer* buf, int buf_len,

[Wez, 2015/07/10 01:18:24]

Should these be scoped_refptr<>&, here and in the streamsocket interface?

[Sergey Ulanov, 2015/07/10 20:48:57]

Done.

+                   const net::CompletionCallback& callback) = 0;
+  virtual int Send(net::IOBuffer* buf, int buf_len,
+                   const net::CompletionCallback& callback) = 0;
+};
+
+}  // namespace protocol
+}  // namespace remoting
+
+#endif  // REMOTING_PROTOCOL_P2P_DATAGRAM_SOCKET_H_