Add support for additional libraries to FE API

pkg/front_end/lib/kernel_generator.dart

Index: pkg/front_end/lib/kernel_generator.dart
diff --git a/pkg/front_end/lib/kernel_generator.dart b/pkg/front_end/lib/kernel_generator.dart
index 086f45adea80856cf9d65959acb630cde6db9b6b..c47ef3320b6375cc796242b12009698bd10f080c 100644
--- a/pkg/front_end/lib/kernel_generator.dart
+++ b/pkg/front_end/lib/kernel_generator.dart
@@ -38,17 +38,12 @@ import 'package:source_span/source_span.dart' show SourceSpan;
 /// needed to access the contents of method bodies).
 Future<Program> kernelForProgram(Uri source, CompilerOptions options) async {
   var loader = await _createLoader(options, entry: source);
-  // TODO(sigmund): delete this. At this time we have no need to explicitly list
-  // VM libraries, since they are normally found by chasing dependencies.
-  // `dart:_builtin` is an exception because it is used by the kernel
-  // transformers to inform the VM about where the main entrypoint is. This is
-  // expected to change, and we should be able to remove these lines at that
-  // point. We check for the presense of `dart:developer` in the targetPatches
-  // to ensure we only load this library while running on the VM.
-  if (options.compileSdk &&
-      options.targetPatches.containsKey(Uri.parse('dart:developer'))) {
-    loader.loadLibrary(Uri.parse('dart:_builtin'));
+
+  if (options.compileSdk) {
+    options.additionalLibraries.forEach((e) { print('$e');

[Paul Berry, 2017/02/13 21:17:42]

Is this temporary debugging code?  Can we delete it before committing?

[Siggi Cherem (dart-lang), 2017/02/13 21:23:11]

doh! yes, I was debugging on a separate script as I uploaded this... sorry for
the noise.

+    loader.loadLibrary(e); });

[Paul Berry, 2017/02/13 21:17:42]

Formatting looks weird; run dartfmt.

[Siggi Cherem (dart-lang), 2017/02/13 21:23:11]

sometimes I make debug code pretty ugly so it is noticeable ;-)

   }
+
   // TODO(sigmund): merge what we have in loadEverything and the logic below in
   // kernelForBuildUnit so there is a single place where we crawl for
   // dependencies.