Add WifiLan validation check

PiperOrigin-RevId: 452402734

internal/platform/implementation/windows/wifi_lan.h

@@ -218,6 +218,9 @@ class WifiLanMedium : public api::WifiLanMedium {
  public:
   ~WifiLanMedium() override = default;
 
+  // Check if a network connection to a primary router exist.
+  bool IsNetworkConnected() const override;
+
   // Starts to advertising
   bool StartAdvertising(const NsdServiceInfo& nsd_service_info) override;
 

internal/platform/implementation/windows/wifi_lan_medium.cc

@@ -36,6 +36,14 @@ namespace location {
 namespace nearby {
 namespace windows {
 
+bool WifiLanMedium::IsNetworkConnected() const {
+  // connection_profile will be null when there's no network adapter or
+  // connection to a network. For example, WiFi isn't connected to an AP/hotspot
+  // and ethernet isn't connected to a router/hub/switch.
+  auto connection_profile = NetworkInformation::GetInternetConnectionProfile();
+  return connection_profile != nullptr;
+}
+
 bool WifiLanMedium::StartAdvertising(const NsdServiceInfo& nsd_service_info) {
   absl::MutexLock lock(&mutex_);