Revert of net: merge two versions of SetTCPNoDelay() function into one

net/socket/tcp_socket_posix.cc

 // Copyright 2013 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.
 
 #include "net/socket/tcp_socket.h"
 
 #include <errno.h>
 #include <netinet/tcp.h>
 #include <sys/socket.h>
 
@@ skipping 26 matching lines @@
 namespace {
 
 // True if OS supports TCP FastOpen.
 bool g_tcp_fastopen_supported = false;
 // True if TCP FastOpen is user-enabled for all connections.
 // TODO(jri): Change global variable to param in HttpNetworkSession::Params.
 bool g_tcp_fastopen_user_enabled = false;
 // True if TCP FastOpen connect-with-write has failed at least once.
 bool g_tcp_fastopen_has_failed = false;
 
+// SetTCPNoDelay turns on/off buffering in the kernel. By default, TCP sockets
+// will wait up to 200ms for more data to complete a packet before transmitting.
+// After calling this function, the kernel will not wait. See TCP_NODELAY in
+// `man 7 tcp`.
+bool SetTCPNoDelay(int fd, bool no_delay) {
+  int on = no_delay ? 1 : 0;
+  int error = setsockopt(fd, IPPROTO_TCP, TCP_NODELAY, &on, sizeof(on));
+  return error == 0;
+}
+
 // SetTCPKeepAlive sets SO_KEEPALIVE.
 bool SetTCPKeepAlive(int fd, bool enable, int delay) {
   // Enabling TCP keepalives is the same on all platforms.
   int on = enable ? 1 : 0;
   if (setsockopt(fd, SOL_SOCKET, SO_KEEPALIVE, &on, sizeof(on))) {
     PLOG(ERROR) << "Failed to set SO_KEEPALIVE on fd: " << fd;
     return false;
   }
 
   // If we disabled TCP keep alive, our work is done here.
@@ skipping 696 matching lines @@
     if (info.tcpi_rtt > 0) {
       *out_rtt = base::TimeDelta::FromMicroseconds(info.tcpi_rtt);
       return true;
     }
   }
 #endif  // defined(TCP_INFO)
   return false;
 }
 
 }  // namespace net