Build authenticating_url_loader_interceptor library.

services/authenticating_url_loader_interceptor/BUILD.gn

Index: services/authenticating_url_loader_interceptor/BUILD.gn
diff --git a/services/authenticating_url_loader_interceptor/BUILD.gn b/services/authenticating_url_loader_interceptor/BUILD.gn
index b90bb14acf4bcdc6d0c357e5f29014e3f0e73917..4306c705bb74f646f5fa07010700e24d47e9c75b 100644
--- a/services/authenticating_url_loader_interceptor/BUILD.gn
+++ b/services/authenticating_url_loader_interceptor/BUILD.gn
@@ -8,6 +8,17 @@ import("//mojo/public/tools/bindings/mojom.gni")
 
 mojo_native_application("authenticating_url_loader_interceptor") {
   sources = [
+    "main.cc",
+  ]
+
+  deps = [
+    ":lib",
+    "//mojo/application",
+  ]
+}
+
+source_set("lib") {
+  sources = [
     "authenticating_url_loader_interceptor.cc",
     "authenticating_url_loader_interceptor.h",
     "authenticating_url_loader_interceptor_app.cc",