Reland: Take 2: Force python test server output to be unbuffered, so it doesn't mix with gtest outpu

net/test/local_test_server_posix.cc

 // Copyright (c) 2012 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/test/local_test_server.h"
 
 #include <poll.h>
 
 #include <vector>
 
@@ skipping 83 matching lines @@
 
 namespace net {
 
 bool LocalTestServer::LaunchPython(const FilePath& testserver_path) {
   // Log is useful in the event you want to run a nearby script (e.g. a test) in
   // the same environment as the TestServer.
   VLOG(1) << "LaunchPython called with PYTHONPATH = " <<
           getenv(kPythonPathEnv);
   CommandLine python_command(FilePath(FILE_PATH_LITERAL("python")));
 
+  // Use unbuffered output, so that testserver output doesn't mix with gtest
+  // output in test log files. See http://crbug.com/147368.
+  python_command.AppendArg("-u");
+
   python_command.AppendArgPath(testserver_path);
   if (!AddCommandLineArguments(&python_command))
     return false;
 
   int pipefd[2];
   if (pipe(pipefd) != 0) {
     PLOG(ERROR) << "Could not create pipe.";
     return false;
   }
 
@@ skipping 47 matching lines @@
 
   if (!ParseServerData(server_data)) {
     LOG(ERROR) << "Could not parse server_data: " << server_data;
     return false;
   }
 
   return true;
 }
 
 }  // namespace net