Infer network connection type from network interface type.

net/base/network_change_notifier.h

Index: net/base/network_change_notifier.h
diff --git a/net/base/network_change_notifier.h b/net/base/network_change_notifier.h
index 6b801bc7c424ead6326bde9bd2441bfeca4e30f9..98ade3ea1d179dd1138dce17db64e25a7b44ea2e 100644
--- a/net/base/network_change_notifier.h
+++ b/net/base/network_change_notifier.h
@@ -5,7 +5,10 @@
 #ifndef NET_BASE_NETWORK_CHANGE_NOTIFIER_H_
 #define NET_BASE_NETWORK_CHANGE_NOTIFIER_H_
 
+#include <vector>
+
 #include "base/basictypes.h"
+#include "base/gtest_prod_util.h"
 #include "base/observer_list_threadsafe.h"
 #include "base/time/time.h"
 #include "net/base/net_export.h"
@@ -17,6 +20,8 @@ namespace net {
 struct DnsConfig;
 class HistogramWatcher;
 class NetworkChangeNotifierFactory;
+struct NetworkInterface;
+typedef std::vector<NetworkInterface> NetworkInterfaceList;
 class URLRequest;
 
 #if defined(OS_LINUX)
@@ -300,15 +305,26 @@ class NET_EXPORT NetworkChangeNotifier {
   // Stores |config| in NetworkState and notifies observers.
   static void SetDnsConfig(const DnsConfig& config);
 
+  // Infer connection type from |GetNetworkList|. If all network interfaces have
+  // the same type, return it, otherwise return CONNECTION_UNKNOWN.
+  static ConnectionType ConnectionTypeFromInterfaces();
+
  private:
   friend class HostResolverImplDnsTest;
   friend class NetworkChangeNotifierAndroidTest;
   friend class NetworkChangeNotifierLinuxTest;
   friend class NetworkChangeNotifierWinTest;
+  FRIEND_TEST_ALL_PREFIXES(NetworkChangeNotifierTest,
+                           InterfacesToConnectionType);
 
   class NetworkState;
   class NetworkChangeCalculator;
 
+  // Infer connection type from |interfaces|. If all network interfaces have
+  // the same type, return it, otherwise return CONNECTION_UNKNOWN.
+  static ConnectionType ConnectionTypeFromInterfaceList(
+      const NetworkInterfaceList& interfaces);
+
   const scoped_refptr<ObserverListThreadSafe<IPAddressObserver> >
       ip_address_observer_list_;
   const scoped_refptr<ObserverListThreadSafe<ConnectionTypeObserver> >