Convert path usage in NetworkListViewBase subclasses to use guids.

ash/common/system/chromeos/network/network_portal_detector_observer.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.
 
 #ifndef ASH_COMMON_SYSTEM_CHROMEOS_NETWORK_NETWORK_PORTAL_DETECTOR_OBSERVER_H_
 #define ASH_COMMON_SYSTEM_CHROMEOS_NETWORK_NETWORK_PORTAL_DETECTOR_OBSERVER_H_
 
 #include <string>
 
 namespace ash {
 
 class NetworkPortalDetectorObserver {
  public:
   virtual ~NetworkPortalDetectorObserver() {}
 
-  // Called when captive portal is detected for a |network|.
-  virtual void OnCaptivePortalDetected(const std::string& service_path) = 0;
+  // Called when captive portal is detected for the network associated with
+  // |guid|.
+  virtual void OnCaptivePortalDetected(const std::string& guid) = 0;
 };
 
 }  // namespace ash
 
 #endif  // ASH_COMMON_SYSTEM_CHROMEOS_NETWORK_NETWORK_PORTAL_DETECTOR_OBSERVER_H_