Quantify initial stability report edge cases.

components/metrics/metrics_log.h

 // Copyright 2014 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.
 
 // This file defines a set of user experience metrics data recorded by
 // the MetricsService.  This is the unit of data that is sent to the server.
 
 #ifndef COMPONENTS_METRICS_METRICS_LOG_H_
 #define COMPONENTS_METRICS_METRICS_LOG_H_
 
@@ skipping 82 matching lines @@
   // A synthetic trial is one that is set up dynamically by code in Chrome. For
   // example, a pref may be mapped to a synthetic trial such that the group
   // is determined by the pref value.
   void RecordEnvironment(
       const std::vector<MetricsProvider*>& metrics_providers,
       const std::vector<variations::ActiveGroupId>& synthetic_trials,
       int64_t install_date,
       int64_t metrics_reporting_enabled_date);
 
   // Loads the environment proto that was saved by the last RecordEnvironment()
-  // call from prefs and clears the pref value. Returns true on success or false
-  // if there was no saved environment in prefs or it could not be decoded.
-  bool LoadSavedEnvironmentFromPrefs();
+  // call from prefs and clears the pref value. On success, returns true and
+  // |app_version| contains the recovered version. Otherwise (if there was no
+  // saved environment in prefs or it could not be decoded), returns false and
+  // |app_version| is empty.
+  bool LoadSavedEnvironmentFromPrefs(std::string* app_version);
 
   // Writes application stability metrics, including stability metrics provided
   // by the specified set of |metrics_providers|. The system profile portion of
   // the log must have already been filled in by a call to RecordEnvironment()
   // or LoadSavedEnvironmentFromPrefs().
   // NOTE: Has the side-effect of clearing the stability prefs..
   //
   // If this log is of type INITIAL_STABILITY_LOG, records additional info such
   // as number of incomplete shutdowns as well as extra breakpad and debugger
   // stats.
@@ skipping 83 matching lines @@
   const base::TimeTicks creation_time_;
 
   PrefService* local_state_;
 
   DISALLOW_COPY_AND_ASSIGN(MetricsLog);
 };
 
 }  // namespace metrics
 
 #endif  // COMPONENTS_METRICS_METRICS_LOG_H_