This is the first pass at making GetIPConfigs asynchronous.

chrome/browser/chromeos/cros/network_library_impl_stub.cc

Index: chrome/browser/chromeos/cros/network_library_impl_stub.cc
diff --git a/chrome/browser/chromeos/cros/network_library_impl_stub.cc b/chrome/browser/chromeos/cros/network_library_impl_stub.cc
index dc2483224fc4f3607c67dd6aa33673b4489f7b57..d0bf25ebd5eb13797949dfc14539d00c45406bcf 100644
--- a/chrome/browser/chromeos/cros/network_library_impl_stub.cc
+++ b/chrome/browser/chromeos/cros/network_library_impl_stub.cc
@@ -691,7 +691,14 @@ void NetworkLibraryImplStub::EnableOfflineMode(bool enable) {
   }
 }
 
-NetworkIPConfigVector NetworkLibraryImplStub::GetIPConfigs(
+void NetworkLibraryImplStub::GetIPConfigs(
+    const std::string& device_path,
+    HardwareAddressFormat format,
+    const NetworkGetIPConfigsCallback& callback) {
+  callback.Run(ip_configs_, hardware_address_);
+}
+
+NetworkIPConfigVector NetworkLibraryImplStub::GetIPConfigsAndBlock(
     const std::string& device_path,
     std::string* hardware_address,
     HardwareAddressFormat format) {