Revert of chromeos: Don't send empty power management policies.

chromeos/dbus/power_policy_controller.h

 // Copyright (c) 2013 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.
 
 #ifndef CHROMEOS_DBUS_POWER_POLICY_CONTROLLER_H_
 #define CHROMEOS_DBUS_POWER_POLICY_CONTROLLER_H_
 
 #include <map>
 #include <string>
 
 #include "base/basictypes.h"
 #include "base/compiler_specific.h"
 #include "chromeos/chromeos_export.h"
+#include "chromeos/dbus/dbus_thread_manager_observer.h"
 #include "chromeos/dbus/power_manager/policy.pb.h"
 #include "chromeos/dbus/power_manager_client.h"
 
 namespace chromeos {
 
 class DBusThreadManager;
 
 // PowerPolicyController is responsible for sending Chrome's assorted power
 // management preferences to the Chrome OS power manager.
 class CHROMEOS_EXPORT PowerPolicyController
-    : public PowerManagerClient::Observer {
+    : public DBusThreadManagerObserver,
+      public PowerManagerClient::Observer {
  public:
   // Note: Do not change these values; they are used by preferences.
   enum Action {
     ACTION_SUSPEND      = 0,
     ACTION_STOP_SESSION = 1,
     ACTION_SHUT_DOWN    = 2,
     ACTION_DO_NOTHING   = 3,
   };
 
   // Values of various power-management-related preferences.
@@ skipping 35 matching lines @@
   static const int kScreenLockAfterOffDelayMs;
 
   PowerPolicyController();
   virtual ~PowerPolicyController();
 
   void Init(DBusThreadManager* manager);
 
   // Updates |prefs_policy_| with |values| and sends an updated policy.
   void ApplyPrefs(const PrefValues& values);
 
+  // Resets |prefs_policy_| to its defaults and sends an updated policy.
+  void ClearPrefs();
+
   // Registers a request to temporarily prevent the screen from getting
   // dimmed or turned off or the system from suspending in response to user
   // inactivity and sends an updated policy.  |reason| is a human-readable
   // description of the reason the lock was created.  Returns a unique ID
   // that can be passed to RemoveWakeLock() later.
   int AddScreenWakeLock(const std::string& reason);
   int AddSystemWakeLock(const std::string& reason);
 
   // Unregisters a request previously created via AddScreenWakeLock() or
   // AddSystemWakeLock() and sends an updated policy.
   void RemoveWakeLock(int id);
 
+  // DBusThreadManagerObserver implementation:
+  virtual void OnDBusThreadManagerDestroying(DBusThreadManager* manager)
+      OVERRIDE;
+
   // PowerManagerClient::Observer implementation:
   virtual void PowerManagerRestarted() OVERRIDE;
 
  private:
   friend class PowerPrefsTest;
 
   typedef std::map<int, std::string> WakeLockMap;
 
   // Sends a policy based on |prefs_policy_| to the power manager.
   void SendCurrentPolicy();
 
-  PowerManagerClient* client_;  // weak
+  // Sends an empty policy to the power manager to reset its configuration.
+  void SendEmptyPolicy();
+
+  DBusThreadManager* manager_;  // not owned
+  PowerManagerClient* client_;  // not owned
 
   // Policy derived from values passed to ApplyPrefs().
   power_manager::PowerManagementPolicy prefs_policy_;
 
   // Was ApplyPrefs() called?
   bool prefs_were_set_;
 
   // Maps from an ID representing a request to prevent the screen from
   // getting dimmed or turned off or to prevent the system from suspending
   // to the reason for the request.
   WakeLockMap screen_wake_locks_;
   WakeLockMap system_wake_locks_;
 
   // Should entries in |screen_wake_locks_| be honored?  If false, screen
   // wake locks are just treated as system wake locks instead.
   bool honor_screen_wake_locks_;
 
   // Next ID to be used by AddScreenWakeLock() or AddSystemWakeLock().
   int next_wake_lock_id_;
 
   DISALLOW_COPY_AND_ASSIGN(PowerPolicyController);
 };
 
 }  // namespace chromeos
 
 #endif  // CHROMEOS_DBUS_POWER_POLICY_CONTROLLER_H_