Expand FeatureList to support FieldTrial association.

base/metrics/field_trial.cc

Index: base/metrics/field_trial.cc
diff --git a/base/metrics/field_trial.cc b/base/metrics/field_trial.cc
index 3f874d85fe4d669ad11e3ba6727e449747bb556a..2ad7517a4bd59e22d0247c8d03c169b014b25829 100644
--- a/base/metrics/field_trial.cc
+++ b/base/metrics/field_trial.cc
@@ -139,6 +139,11 @@ const std::string& FieldTrial::group_name() {
   return group_name_;
 }
 
+const std::string& FieldTrial::GetGroupNameWithoutActivation() {
+  FinalizeGroupChoice();
+  return group_name_;
+}
+
 void FieldTrial::SetForced() {
   // We might have been forced before (e.g., by CreateFieldTrial) and it's
   // first come first served, e.g., command line switch has precedence.