Support Using ScopedFeatureList in BrowserTest

chrome/browser/process_singleton_browsertest.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.
 
 // This test validates that the ProcessSingleton class properly makes sure
 // that there is only one main browser process.
 //
 // It is currently compiled and run on Windows and Posix(non-Mac) platforms.
 // Mac uses system services and ProcessSingletonMac is a noop.  (Maybe it still
 // makes sense to test that the system services are giving the behavior we
@@ skipping 17 matching lines @@
 #include "base/single_thread_task_runner.h"
 #include "base/synchronization/waitable_event.h"
 #include "base/test/test_timeouts.h"
 #include "base/threading/thread.h"
 #include "build/build_config.h"
 #include "chrome/common/chrome_constants.h"
 #include "chrome/common/chrome_paths.h"
 #include "chrome/common/chrome_switches.h"
 #include "chrome/test/base/in_process_browser_test.h"
 #include "chrome/test/base/test_launcher_utils.h"
+#include "content/public/common/content_switches.h"
 
 namespace {
 
 // This is for the code that is to be ran in multiple threads at once,
 // to stress a race condition on first process start.
 // We use the thread safe ref counted base class so that we can use the
 // base::Bind to run the StartChrome methods in many threads.
 class ChromeStarter : public base::RefCountedThreadSafe<ChromeStarter> {
  public:
   ChromeStarter(base::TimeDelta timeout, const base::FilePath& user_data_dir)
@@ skipping 24 matching lines @@
     command_line.AppendSwitchPath(switches::kUserDataDir, user_data_dir_);
 
     if (first_run)
       command_line.AppendSwitch(switches::kForceFirstRun);
     else
       command_line.AppendSwitch(switches::kNoFirstRun);
 
     // Add the normal test-mode switches, except for the ones we're adding
     // ourselves.
     base::CommandLine standard_switches(base::CommandLine::NO_PROGRAM);
+
+    // Turn off preconnects because they break the brittle python webserver;
+    // see http://crbug.com/60035.
+    command_line.AppendSwitchASCII(switches::kDisableFeatures,
+                                   "NetworkPrediction");

[Ilya Sherman, 2017/06/09 20:19:28]

Is this actually necessary?  I don't think this test uses the Python webserver
-- does it?

+
     test_launcher_utils::PrepareBrowserCommandLineForTests(&standard_switches);
     const base::CommandLine::SwitchMap& switch_map =
         standard_switches.GetSwitches();
     for (base::CommandLine::SwitchMap::const_iterator i = switch_map.begin();
          i != switch_map.end(); ++i) {
       const std::string& switch_name = i->first;
       if (switch_name == switches::kUserDataDir ||
           switch_name == switches::kForceFirstRun ||
           switch_name == switches::kNoFirstRun)
         continue;
@@ skipping 225 matching lines @@
     // "There can be only one!" :-)
     ASSERT_EQ(static_cast<size_t>(1), pending_starters.size());
     size_t last_index = pending_starters.front();
     pending_starters.clear();
     if (chrome_starters_[last_index]->process_.IsValid()) {
       KillProcessTree(chrome_starters_[last_index]->process_);
       chrome_starters_[last_index]->done_event_.Wait();
     }
   }
 }