Store field trial parameters in shared memory

components/variations/variations_seed_processor.cc

Index: components/variations/variations_seed_processor.cc
diff --git a/components/variations/variations_seed_processor.cc b/components/variations/variations_seed_processor.cc
index 50c5cdc7dc39219208130d93a1177c97461ff41d..8c67a51cdfef959671f298f323620af48e24ee02 100644
--- a/components/variations/variations_seed_processor.cc
+++ b/components/variations/variations_seed_processor.cc
@@ -86,6 +86,9 @@ void ForceExperimentState(
   RegisterExperimentParams(study, experiment);
   RegisterVariationIds(experiment, study.name());
   if (study.activation_type() == Study_ActivationType_ACTIVATION_AUTO) {
+    // This call must happen after all params have been registered for the
+    // trial. Otherwise, since we look up params by trial and group name, the
+    // params won't be registered under the correct key.
     trial->group();
     // UI Strings can only be overridden from ACTIVATION_AUTO experiments.
     ApplyUIStringOverrides(experiment, override_callback);
@@ -310,6 +313,9 @@ void VariationsSeedProcessor::CreateTrialFromStudy(
     RegisterFeatureOverrides(processed_study, trial.get(), feature_list);
 
   if (study.activation_type() == Study_ActivationType_ACTIVATION_AUTO) {
+    // This call must happen after all params have been registered for the
+    // trial. Otherwise, since we look up params by trial and group name, the
+    // params won't be registered under the correct key.
     const std::string& group_name = trial->group_name();
 
     // Don't try to apply overrides if none of the experiments in this study had