Add a function to get Wifi SSID to net_util.

net/base/net_util.h

Index: net/base/net_util.h
diff --git a/net/base/net_util.h b/net/base/net_util.h
index 9e9dbad4613914bf257bd274edb692c79e947ee3..a045b8bda9c5d1485ae68eb28ae331e68863ffb7 100644
--- a/net/base/net_util.h
+++ b/net/base/net_util.h
@@ -496,6 +496,14 @@ enum HostAddressSelectionPolicy {
 NET_EXPORT bool GetNetworkList(NetworkInterfaceList* networks,
                                int policy);
 
+// Gets the current Wi-Fi SSID based on |interfaces|. Returns
+// empty string if there are no interfaces or if two interfaces have different
+// connection types. Otherwise returns the SSID of all interfaces if they have
+// the same SSID. This is adapted from
+// NetworkChangeNotifier::ConnectionTypeFromInterfaceList.
+NET_EXPORT std::string GetWifiSSIDFromInterfaceList(
+    const NetworkInterfaceList& interfaces);
+
 // General category of the IEEE 802.11 (wifi) physical layer operating mode.
 enum WifiPHYLayerProtocol {
   // No wifi support or no associated AP.