Store field trial parameters in shared memory

base/metrics/field_trial_param_associator.cc

Index: base/metrics/field_trial_param_associator.cc
diff --git a/base/metrics/field_trial_param_associator.cc b/base/metrics/field_trial_param_associator.cc
index b96cc396df874689af034691d9479a780ae78417..8933f48bb9a518cf5d00e7f267ff36be33ee0a1f 100644
--- a/base/metrics/field_trial_param_associator.cc
+++ b/base/metrics/field_trial_param_associator.cc
@@ -23,26 +23,27 @@ bool FieldTrialParamAssociator::AssociateFieldTrialParams(
     const FieldTrialParams& params) {
   AutoLock scoped_lock(lock_);
 
-  if (FieldTrialList::IsTrialActive(trial_name))
-    return false;
+  return AssociateParamsWhileLocked(trial_name, group_name, params);
+}
 
-  const FieldTrialKey key(trial_name, group_name);
-  if (ContainsKey(field_trial_params_, key))
-    return false;
+bool FieldTrialParamAssociator::GetFieldTrialParams(
+    const std::string& trial_name,
+    FieldTrialParams* params) {
+  AutoLock scoped_lock(lock_);
 
-  field_trial_params_[key] = params;
-  return true;
+  const std::string group_name = FieldTrialList::FindFullName(trial_name);
+  return GetFieldTrialParams(trial_name, group_name, params);
 }
 
 bool FieldTrialParamAssociator::GetFieldTrialParams(
     const std::string& trial_name,
+    const std::string& group_name,
     FieldTrialParams* params) {
   AutoLock scoped_lock(lock_);
 
-  const std::string group_name = FieldTrialList::FindFullName(trial_name);
   const FieldTrialKey key(trial_name, group_name);
   if (!ContainsKey(field_trial_params_, key))
-    return false;
+    return GetParamsFromSharedMemory(trial_name, group_name, params);
 
   *params = field_trial_params_[key];
   return true;
@@ -53,4 +54,29 @@ void FieldTrialParamAssociator::ClearAllParamsForTesting() {
   field_trial_params_.clear();
 }
 
+bool FieldTrialParamAssociator::GetParamsFromSharedMemory(
+    const std::string& trial_name,
+    const std::string& group_name,
+    FieldTrialParams* params) {
+  bool result = FieldTrialList::FindParams(trial_name, params);
+  if (result)
+    AssociateParamsWhileLocked(trial_name, group_name, *params);
+  return result;
+}
+
+bool FieldTrialParamAssociator::AssociateParamsWhileLocked(
+    const std::string& trial_name,
+    const std::string& group_name,
+    const FieldTrialParams& params) {
+  if (FieldTrialList::IsTrialActive(trial_name))
+    return false;
+
+  const FieldTrialKey key(trial_name, group_name);
+  if (ContainsKey(field_trial_params_, key))
+    return false;
+
+  field_trial_params_[key] = params;
+  return true;
+}
+
 }  // namespace base