Support toggling Wi-Fi with keyboard shortcut.

ash/system/network/network_observer.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.
 
 #ifndef ASH_SYSTEM_NETWORK_NETWORK_OBSERVER_H
 #define ASH_SYSTEM_NETWORK_NETWORK_OBSERVER_H
 
 #include "base/string16.h"
 
 namespace ash {
@@ skipping 24 matching lines @@
   // Sets a network error notification. |error_type| identifies the type of
   // error. |delegate|->NotificationLinkClicked() will be called if |link_text|
   // is clicked (if supplied, |link_text| may be empty).
   virtual void SetNetworkError(NetworkTrayDelegate* delegate,
                                ErrorType error_type,
                                const string16& title,
                                const string16& message,
                                const string16& link_text) = 0;
   // Clears the error notification for |error_type|.
   virtual void ClearNetworkError(ErrorType error_type) = 0;
+
+  // Called when the user attempted to toggle Wi-Fi enable/disable.
+  // NOTE: Toggling is asynchronous and subsequent calls to query the current
+  // state may return the old value.
+  virtual void OnWillToggleWifi() = 0;
 };
 
 }  // namespace ash
 
 #endif  // ASH_SYSTEM_NETWORK_NETWORK_OBSERVER_H