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 391bfc5f7cdb2976b03e54d9f27c4a7badf33304..5c82eb5174c37a46cab28b57e8ea6c77b9d6dd30 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.