Add NetworkChangeNotifier connectivity events to the NetLog.

net/base/network_change_notifier.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 NET_BASE_NETWORK_CHANGE_NOTIFIER_H_
 #define NET_BASE_NETWORK_CHANGE_NOTIFIER_H_
 
 #include "base/basictypes.h"
 #include "base/observer_list_threadsafe.h"
 #include "net/base/net_export.h"
@@ skipping 145 matching lines @@
   // there's no reason to use the API in this risky way, so don't do it.
   static void RemoveIPAddressObserver(IPAddressObserver* observer);
   static void RemoveConnectionTypeObserver(ConnectionTypeObserver* observer);
   static void RemoveDNSObserver(DNSObserver* observer);
 
   // Allow unit tests to trigger notifications.
   static void NotifyObserversOfIPAddressChangeForTests() {
     NotifyObserversOfIPAddressChange();
   }
 
+  // Return a string equivalent to |type|.
+  static const char* ConnectionTypeToString(ConnectionType type);
+
   // Let the NetworkChangeNotifier know we received some data.
   // This is used strictly for producing histogram data about the accuracy of
   // the NetworkChangenotifier's online detection.
   static void NotifyDataReceived(const GURL& source);
 
   // Register the Observer callbacks for producing histogram data.  This
   // should be called from the network thread to avoid race conditions.
   static void InitHistogramWatcher();
 
  protected:
@@ skipping 53 matching lines @@
 
   // A little-piggy-back observer that simply logs UMA histogram data.
   scoped_ptr<HistogramWatcher> histogram_watcher_;
 
   DISALLOW_COPY_AND_ASSIGN(NetworkChangeNotifier);
 };
 
 }  // namespace net
 
 #endif  // NET_BASE_NETWORK_CHANGE_NOTIFIER_H_