FieldTrial - Use ObserverListThreadSafe instead of

base/metrics/field_trial.h

 // Copyright (c) 2012 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 // FieldTrial is a class for handling details of statistical experiments
 // performed by actual users in the field (i.e., in a shipped or beta product).
 // All code is called exclusively on the UI thread currently.
 //
 // The simplest example is an experiment to see whether one of two options
 // produces "better" results across our user population.  In that scenario, UMA
@@ skipping 64 matching lines @@
 #define BASE_METRICS_FIELD_TRIAL_H_
 #pragma once
 
 #include <map>
 #include <string>
 #include <vector>
 
 #include "base/base_export.h"
 #include "base/gtest_prod_util.h"
 #include "base/memory/ref_counted.h"
-#include "base/observer_list.h"
+#include "base/observer_list_threadsafe.h"
 #include "base/synchronization/lock.h"
 #include "base/time.h"
 
 namespace base {
 
 class FieldTrialList;
 
 class BASE_EXPORT FieldTrial : public RefCounted<FieldTrial> {
  public:
   typedef int Probability;  // Probability type for being selected in a trial.
@@ skipping 153 matching lines @@
  public:
   // Define a separator character to use when creating a persistent form of an
   // instance.  This is intended for use as a command line argument, passed to a
   // second process to mimic our state (i.e., provide the same group name).
   static const char kPersistentStringSeparator;  // Currently a slash.
 
   // Define expiration year in future. It is initialized to two years from Now.
   static int kExpirationYearInFuture;
 
   // Observer is notified when a FieldTrial's group is selected.
-  class Observer {
+  class BASE_EXPORT Observer {
    public:
     // Notify observers when FieldTrials's group is selected.
     virtual void OnFieldTrialGroupFinalized(const std::string& trial_name,
                                             const std::string& group_name) = 0;
 
    protected:
     virtual ~Observer() {}
   };
 
   // This singleton holds the global list of registered FieldTrials.
@@ skipping 146 matching lines @@
 
   // Lock for access to registered_.
   base::Lock lock_;
   RegistrationList registered_;
 
   // An opaque, diverse ID for this client that does not change
   // between sessions, or the empty string if not initialized.
   std::string client_id_;
 
   // List of observers to be notified when a group is selected for a FieldTrial.
-  ObserverList<Observer> observer_list_;
+  scoped_refptr<ObserverListThreadSafe<Observer> > observer_list_;
 
   DISALLOW_COPY_AND_ASSIGN(FieldTrialList);
 };
 
 }  // namespace base
 
 #endif  // BASE_METRICS_FIELD_TRIAL_H_