Add WiFi SSID getter to NetworkChangeNotifier.

net/base/network_change_notifier.cc

Index: net/base/network_change_notifier.cc
diff --git a/net/base/network_change_notifier.cc b/net/base/network_change_notifier.cc
index ec45a4e2ea458e0887e0fcad68bf56bf29c1d1a0..c756c5ebfe9ff540155c1dafd3ed64b0b47a25ac 100644
--- a/net/base/network_change_notifier.cc
+++ b/net/base/network_change_notifier.cc
@@ -48,6 +48,7 @@ class MockNetworkChangeNotifier : public NetworkChangeNotifier {
   ConnectionType GetCurrentConnectionType() const override {
     return CONNECTION_UNKNOWN;
   }
+  std::string GetCurrentWiFiSSID() const override { return ""; }
 };
 
 }  // namespace
@@ -536,6 +537,12 @@ NetworkChangeNotifier::GetConnectionType() {
       CONNECTION_UNKNOWN;
 }
 
+std::string NetworkChangeNotifier::GetWiFiSSID() {
+  return g_network_change_notifier
+             ? g_network_change_notifier->GetCurrentWiFiSSID()
+             : "";
+}
+
 // static
 double NetworkChangeNotifier::GetMaxBandwidth() {
   return g_network_change_notifier ?