Share field trial allocator on zygote-using Linuxes

components/variations/child_process_field_trial_syncer_unittest.cc

 // Copyright 2016 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 "components/variations/child_process_field_trial_syncer.h"
 
 #include <string>
 #include <utility>
 #include <vector>
 
@@ skipping 37 matching lines @@
                                                    const std::string& b) {
   return std::make_pair(a, b);
 }
 
 }  // namespace
 
 TEST(ChildProcessFieldTrialSyncerTest, FieldTrialState) {
   base::MessageLoop message_loop;
   base::FieldTrialList field_trial_list(nullptr);
   base::FieldTrialList::CreateTrialsFromCommandLine(
-      *base::CommandLine::ForCurrentProcess(), "field_trial_handle_switch");
+      *base::CommandLine::ForCurrentProcess(), "field_trial_handle_switch", -1);

[Alexei Svitkine (slow), 2016/11/28 16:56:13]

You don't document anywhere why it's OK to pass a -1 for the last param.

[lawrencewu, 2016/11/29 14:38:07]

Changed things around so we don't need to pass in the last param anymore.

 
   base::FieldTrial* trial1 = base::FieldTrialList::CreateFieldTrial("A", "G1");
   base::FieldTrial* trial2 = base::FieldTrialList::CreateFieldTrial("B", "G2");
   base::FieldTrial* trial3 = base::FieldTrialList::CreateFieldTrial("C", "G3");
   // Activate trial3 before command line is produced.
   trial1->group();
 
   std::string states_string;
   base::FieldTrialList::AllStatesToString(&states_string);
 
@@ skipping 19 matching lines @@
   trial3->group();
   // Notifications from field trial activation actually happen via posted tasks,
   // so invoke the run loop.
   base::RunLoop().RunUntilIdle();
 
   ASSERT_EQ(2U, observer.observed_entries_count());
   EXPECT_EQ(MakeStringPair("C", "G3"), observer.get_observed_entry(1));
 }
 
 }  // namespace variations