Adds a method to TCPServerSocket to adopt a socket.

net/socket/tcp_server_socket.cc

Index: net/socket/tcp_server_socket.cc
diff --git a/net/socket/tcp_server_socket.cc b/net/socket/tcp_server_socket.cc
index 22211cd9496626e62c194ebf0ea82391ca5e3cb1..779a24d16cebf5108e864eb7994fd33e5ef3a5c8 100644
--- a/net/socket/tcp_server_socket.cc
+++ b/net/socket/tcp_server_socket.cc
@@ -10,6 +10,7 @@
 #include "base/bind_helpers.h"
 #include "base/logging.h"
 #include "net/base/net_errors.h"
+#include "net/socket/socket_descriptor.h"
 #include "net/socket/tcp_client_socket.h"
 
 namespace net {
@@ -17,6 +18,10 @@ namespace net {
 TCPServerSocket::TCPServerSocket(NetLog* net_log, const NetLogSource& source)
     : socket_(nullptr, net_log, source), pending_accept_(false) {}
 
+int TCPServerSocket::AdoptSocket(SocketDescriptor socket) {
+  return socket_.AdoptUnconnectedSocket(socket);
+}
+
 TCPServerSocket::~TCPServerSocket() {
 }