Fix getting initially active trials with shared memory.

chrome/common/variations/child_process_field_trial_syncer.cc

Index: chrome/common/variations/child_process_field_trial_syncer.cc
diff --git a/chrome/common/variations/child_process_field_trial_syncer.cc b/chrome/common/variations/child_process_field_trial_syncer.cc
index d559b1f745edbf8dc38d56d500028723aab86ec9..44a8b94c1cae41a4a94bb4f44f1d938d3b673f0d 100644
--- a/chrome/common/variations/child_process_field_trial_syncer.cc
+++ b/chrome/common/variations/child_process_field_trial_syncer.cc
@@ -31,9 +31,8 @@ void ChildProcessFieldTrialSyncer::InitFieldTrialObserving(
   // browser of these activations now. To detect these, take the set difference
   // of currently active trials with the initially active trials.
   base::FieldTrial::ActiveGroups initially_active_trials;
-  base::FieldTrialList::GetActiveFieldTrialGroupsFromString(
-      command_line.GetSwitchValueASCII(switches::kForceFieldTrials),
-      &initially_active_trials);
+  base::FieldTrialList::GetInitiallyActiveFieldTrials(command_line,
+                                                      &initially_active_trials);
   std::set<std::string> initially_active_trials_set;
   for (const auto& entry : initially_active_trials) {
     initially_active_trials_set.insert(std::move(entry.trial_name));