1 // Copyright 2014 The Chromium Authors. All rights reserved. 2 // Use of this source code is governed by a BSD-style license that can be 3 // found in the LICENSE file. 4 5 #ifndef COMPONENTS_METRICS_CLEAN_EXIT_BEACON_H_ 6 #define COMPONENTS_METRICS_CLEAN_EXIT_BEACON_H_ 7 8 #include "base/macros.h" 9 #include "base/strings/string16.h" 10 11 class PrefService; 12 13 namespace metrics { 14 15 // Reads and updates a beacon used to detect whether the previous browser 16 // process exited cleanly. 17 class CleanExitBeacon { 18 public: 19 // Instantiates a CleanExitBeacon whose value is stored in |local_state|. 20 // |local_state| must be fully initialized. 21 // On Windows, |backup_registry_key| is used to store a backup of the beacon. 22 // It is ignored on other platforms. 23 CleanExitBeacon( 24 const base::string16& backup_registry_key, 25 PrefService* local_state); 26 27 ~CleanExitBeacon(); 28 29 // Returns the original value of the beacon. 30 bool exited_cleanly() const { return initial_value_; } 31 32 // Writes the provided beacon value. 33 void WriteBeaconValue(bool exited_cleanly); 34 35 private: 36 PrefService* const local_state_; 37 const bool initial_value_; 38 const base::string16 backup_registry_key_; 39 40 DISALLOW_COPY_AND_ASSIGN(CleanExitBeacon); 41 }; 42 43 } // namespace metrics 44 45 #endif // COMPONENTS_METRICS_CLEAN_EXIT_BEACON_H_ 46
