Adds a method to TCPServerSocket to adopt a socket.

net/socket/tcp_socket_posix.h

Index: net/socket/tcp_socket_posix.h
diff --git a/net/socket/tcp_socket_posix.h b/net/socket/tcp_socket_posix.h
index f5ba10abc34a5f00916dffc3792dccda996e063f..0274056d2e7d53d8113490c57837d73a578dce6f 100644
--- a/net/socket/tcp_socket_posix.h
+++ b/net/socket/tcp_socket_posix.h
@@ -16,6 +16,7 @@
 #include "net/base/completion_callback.h"
 #include "net/base/net_export.h"
 #include "net/log/net_log_with_source.h"
+#include "net/socket/socket_descriptor.h"
 #include "net/socket/socket_performance_watcher.h"
 
 namespace base {
@@ -43,8 +44,15 @@ class NET_EXPORT TCPSocketPosix {
 
   int Open(AddressFamily family);
 
-  // Takes ownership of |socket_fd|.
-  int AdoptConnectedSocket(int socket_fd, const IPEndPoint& peer_address);
+  // Takes ownership of |socket|, which is known to already be connected to the
+  // given peer address. However, peer address may be the empty address, for
+  // compatibility. The given peer address will be returned by GetPeerAddress.
+  int AdoptConnectedSocket(SocketDescriptor socket,
+                           const IPEndPoint& peer_address);
+  // Takes ownership of |socket|, which may or may not be open, bound, or
+  // listening. The caller must determine the state of the socket based on its
+  // provenance and act accordingly.
+  int AdoptUnconnectedSocket(SocketDescriptor socket);
 
   int Bind(const IPEndPoint& address);