Add WiFi SSID getter to NetworkChangeNotifier.

chrome/browser/prerender/prerender_browsertest.cc

Index: chrome/browser/prerender/prerender_browsertest.cc
diff --git a/chrome/browser/prerender/prerender_browsertest.cc b/chrome/browser/prerender/prerender_browsertest.cc
index beddbb362f2735431ed7d3a512db67e72fc9922d..a6aaa81d6f6fc42cd7ec3423b211c891efb591a3 100644
--- a/chrome/browser/prerender/prerender_browsertest.cc
+++ b/chrome/browser/prerender/prerender_browsertest.cc
@@ -136,6 +136,7 @@ class MockNetworkChangeNotifierWIFI : public NetworkChangeNotifier {
   ConnectionType GetCurrentConnectionType() const override {
     return NetworkChangeNotifier::CONNECTION_WIFI;
   }
+  std::string GetCurrentWiFiSSID() const override { return ""; }
 };
 
 class MockNetworkChangeNotifier4G : public NetworkChangeNotifier {
@@ -143,6 +144,7 @@ class MockNetworkChangeNotifier4G : public NetworkChangeNotifier {
   ConnectionType GetCurrentConnectionType() const override {
     return NetworkChangeNotifier::CONNECTION_4G;
   }
+  std::string GetCurrentWiFiSSID() const override { return ""; }
 };
 
 // Constants used in the test HTML files.