Observe IP address change in connectivity_checker.

chromecast/net/connectivity_checker.h

Index: chromecast/net/connectivity_checker.h
diff --git a/chromecast/net/connectivity_checker.h b/chromecast/net/connectivity_checker.h
index 28bde9a97249b5b45c724657ed8b2c5839281bba..c52b8a624da5b5595e8d8bddddcd5a59609e07a8 100644
--- a/chromecast/net/connectivity_checker.h
+++ b/chromecast/net/connectivity_checker.h
@@ -28,7 +28,8 @@ namespace chromecast {
 class ConnectivityChecker
     : public base::RefCountedThreadSafe<ConnectivityChecker>,
       public net::URLRequest::Delegate,
-      public net::NetworkChangeNotifier::ConnectionTypeObserver {
+      public net::NetworkChangeNotifier::ConnectionTypeObserver,
+      public net::NetworkChangeNotifier::IPAddressObserver {
  public:
   class ConnectivityObserver {
    public:
@@ -72,6 +73,9 @@ class ConnectivityChecker
   void OnConnectionTypeChanged(
       net::NetworkChangeNotifier::ConnectionType type) override;
 
+  // net::NetworkChangeNotifier::IPAddressObserver implementation:
+  void OnIPAddressChanged() override;
+
   // Cancels current connectivity checking in progress.
   void Cancel();