More instrumentation to diagnose an Android renderer crash.

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 337 matching lines @@
   ~FieldTrialList();
 
   // TODO(asvitkine): Temporary function to diagnose http://crbug.com/359406.
   // Remove when that bug is fixed. This enables using a global map that checks
   // the state of field trials between possible FieldTrialList instances. If
   // enabled, a CHECK will be hit if it's seen that a field trial is given a
   // different state then what was specified to a renderer process launch
   // command line.
   static void EnableGlobalStateChecks();
 
+  // TODO(asvitkine): Temporary function to diagnose http://crbug.com/359406.
+  // Remove when that bug is fixed. This returns a unique token generated during
+  // FieldTrialList construction. This is used to verify that this value stays
+  // consistent between renderer process invocation.

[Nico, 2016/05/09 20:48:11]

invocationS?

[Alexei Svitkine (slow), 2016/05/09 20:50:40]

Done.

+  static int32_t GetDebugToken();
+
   // Get a FieldTrial instance from the factory.
   //
   // |name| is used to register the instance with the FieldTrialList class,
   // and can be used to find the trial (only one trial can be present for each
   // name). |default_group_name| is the name of the default group which will
   // be chosen if none of the subsequent appended groups get to be chosen.
   // |default_group_number| can receive the group number of the default group as
   // AppendGroup returns the number of the subsequence groups. |trial_name| and
   // |default_group_name| may not be empty but |default_group_number| can be
   // NULL if the value is not needed.
@@ skipping 158 matching lines @@
 
   // List of observers to be notified when a group is selected for a FieldTrial.
   scoped_refptr<ObserverListThreadSafe<Observer> > observer_list_;
 
   DISALLOW_COPY_AND_ASSIGN(FieldTrialList);
 };
 
 }  // namespace base
 
 #endif  // BASE_METRICS_FIELD_TRIAL_H_