make SetReceiveBufferSize and SetSendBufferSize return net error codes (instead of bools)

net/socket/tcp_socket_libevent.h

Index: net/socket/tcp_socket_libevent.h
diff --git a/net/socket/tcp_socket_libevent.h b/net/socket/tcp_socket_libevent.h
index a50caf0ad597f0cb20ca0bedcc687c8709748bc5..9ef235be85d408a07b91b9d430b948f4436cfb40 100644
--- a/net/socket/tcp_socket_libevent.h
+++ b/net/socket/tcp_socket_libevent.h
@@ -61,8 +61,8 @@ class NET_EXPORT TCPSocketLibevent : public base::NonThreadSafe {
   // - SetKeepAlive(true, 45).
   void SetDefaultOptionsForClient();
   int SetAddressReuse(bool allow);
-  bool SetReceiveBufferSize(int32 size);
-  bool SetSendBufferSize(int32 size);
+  int SetReceiveBufferSize(int32 size);
+  int SetSendBufferSize(int32 size);
   bool SetKeepAlive(bool enable, int delay);
   bool SetNoDelay(bool no_delay);