Add DiscoveryNetworkMonitor implementation

chrome/browser/extensions/api/dial/dial_api.cc

Index: chrome/browser/extensions/api/dial/dial_api.cc
diff --git a/chrome/browser/extensions/api/dial/dial_api.cc b/chrome/browser/extensions/api/dial/dial_api.cc
index e97f90fa0b260780ad189b0ce32a5c585dd4c248..6b59f29df083377b7a12061143e5f69b45d23708 100644
--- a/chrome/browser/extensions/api/dial/dial_api.cc
+++ b/chrome/browser/extensions/api/dial/dial_api.cc
@@ -261,4 +261,29 @@ void DialFetchDeviceDescriptionFunction::OnFetchError(
   SendResponse(false);
 }
 
+DialGetNetworkIdFunction::DialGetNetworkIdFunction() {}
+
+DialGetNetworkIdFunction::~DialGetNetworkIdFunction() {}
+
+bool DialGetNetworkIdFunction::RunAsync() {
+  auto* network_monitor = DiscoveryNetworkMonitor::GetInstance();
+  // If we are the first to call the DiscoveryNetworkMonitor, it will have no
+  // network state.  Force a refresh to be sure the network ID is populated.
+  network_monitor->ForceNetworkInfoRefresh(
+      base::Bind(&DialGetNetworkIdFunction::NetworkIdCallback, this));
+  return true;
+}
+
+void DialGetNetworkIdFunction::NetworkIdCallback() {
+  const auto* network_monitor = DiscoveryNetworkMonitor::GetInstance();
+  std::string network_id(network_monitor->GetNetworkId());
+  if (network_id.size() == 0) {
+    SetResult(base::MakeUnique<base::Value>(std::string("unknown")));
+    SendResponse(true);
+    return;
+  }
+  SetResult(base::MakeUnique<base::Value>(network_id));
+  SendResponse(true);
+}
+
 }  // namespace extensions