Store field trial parameters in shared memory

base/metrics/field_trial_param_associator.h

Index: base/metrics/field_trial_param_associator.h
diff --git a/base/metrics/field_trial_param_associator.h b/base/metrics/field_trial_param_associator.h
index 214e146966eebbdf8fe0888f4c705eea1f251fb0..09969efcb36faa904d5d4b5e390e19df0fb9e5ec 100644
--- a/base/metrics/field_trial_param_associator.h
+++ b/base/metrics/field_trial_param_associator.h
@@ -33,10 +33,15 @@ class BASE_EXPORT FieldTrialParamAssociator {
                                  const std::string& group_name,
                                  const FieldTrialParams& params);
 
-  // Gets the parameters for a field trial and its chosen group.
+  // Gets the parameters for a field trial.
   bool GetFieldTrialParams(const std::string& trial_name,
                            FieldTrialParams* params);
 
+  // Gets the parameters for a field trial. Caller must lock.
+  bool GetFieldTrialParamsWhileLocked(const std::string& trial_name,

[Alexei Svitkine (slow), 2016/11/01 14:57:16]

This is not correct.

The lock in question is the one in this object. Since it's private, the caller
can't lock it.

Why not just use GetFieldTrialParams()?

[lawrencewu, 2016/11/01 18:29:05]

Fixed by overloading GetFieldTrialParams() and calling that.

+                                      const std::string& group_name,
+                                      FieldTrialParams* params);
+
   // Clears the internal field_trial_params_ mapping.
   void ClearAllParamsForTesting();