[CrOS Tether] Disconnect cleanly from active Tether networks when the user logs out or the Tether c…

chromeos/components/tether/pref_names.h

 // Copyright 2017 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_COMPONENTS_TETHER_PREF_NAMES_H_
 #define CHROMEOS_COMPONENTS_TETHER_PREF_NAMES_H_
 
 namespace chromeos {
 
 namespace tether {
@@ skipping 21 matching lines @@
 extern const char kActiveHostDeviceId[];
 
 // The tether network GUID of the active host. If there is no active host, the
 // value at this key is "".
 extern const char kTetherNetworkGuid[];
 
 // The Wi-Fi network GUID of the active host. If there is no active host, the
 // value at this key is "".
 extern const char kWifiNetworkGuid[];
 
+// The Wi-Fi network GUID that is currently being disconnected. When
+// disconnecting under normal circumstances, this value is set when a
+// disconnection is initiated and is cleared when a disconnection completes.
+// However, when a disconnection is triggered by the user logging out, the
+// disconnection flow cannot complete before Chrome shuts down (due to the
+// asynchronous nature of the network stack), so this GUID remains in prefs.
+// When the Tether component starts up again (the next time the user logs in),
+// this GUID is fetched, the associated network configuration is removed, and
+// the GUID is cleared from prefs.
+extern const char kDisconnectingWifiNetworkGuid[];
+
 }  // namespace prefs
 
 }  // namespace tether
 
 }  // namespace chromeos
 
 #endif  // CHROMEOS_COMPONENTS_TETHER_PREF_NAMES_H_