First patch in making destructors of refcounted objects private.

base/field_trial.h

 // Copyright (c) 2006-2009 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 98 matching lines @@
   // if the group's name is empty, a name of "_" concatenated with the group
   // number is used as the group name.
   std::string group_name() const { return group_name_; }
 
   // Helper function for the most common use: as an argument to specifiy the
   // name of a HISTOGRAM.  Use the original histogram name as the name_prefix.
   static std::string MakeName(const std::string& name_prefix,
                               const std::string& trial_name);
 
  private:
+  friend class base::RefCounted<FieldTrial>;
+
+  virtual ~FieldTrial() {}

[M-A Ruel, 2009/11/05 20:31:28]

why virtual?

[jam, 2009/11/05 21:52:37]

Done.

+
   // The name of the field trial, as can be found via the FieldTrialList.
   // This is empty of the trial is not in the experiment.
   const std::string name_;
 
   // The maximu sum of all probabilities supplied, which corresponds to 100%.
   // This is the scaling factor used to adjust supplied probabilities.
   Probability divisor_;
 
   // The randomly selected probability that is used to select a group (or have
   // the instance not participate).  It is the product of divisor_ and a random
@@ skipping 92 matching lines @@
 
   // Lock for access to registered_.
   Lock lock_;
   RegistrationList registered_;
 
   DISALLOW_COPY_AND_ASSIGN(FieldTrialList);
 };
 
 #endif  // BASE_FIELD_TRIAL_H_