dart2js: keep track of non-final static fields.

pkg/compiler/lib/src/js_emitter/program_builder.dart

Index: pkg/compiler/lib/src/js_emitter/program_builder.dart
diff --git a/pkg/compiler/lib/src/js_emitter/program_builder.dart b/pkg/compiler/lib/src/js_emitter/program_builder.dart
index 0b901412ee4ef0eb11f20b8a15237cb5429b5103..8b55f58ca95c810128231e62e3dd7851610a6a42 100644
--- a/pkg/compiler/lib/src/js_emitter/program_builder.dart
+++ b/pkg/compiler/lib/src/js_emitter/program_builder.dart
@@ -199,14 +199,11 @@ class ProgramBuilder {
   }
 
   List<StaticField> _buildStaticNonFinalFields(LibrariesMap librariesMap) {
-    // TODO(floitsch): handle static non-final fields correctly with deferred
-    // libraries.
-    if (librariesMap != _registry.mainLibrariesMap) {
-      return const <StaticField>[];
-    }
-    Iterable<VariableElement> staticNonFinalFields =
-        backend.constants.getStaticNonFinalFieldsForEmission();
-    return Elements.sortedByPosition(staticNonFinalFields)
+    List<VariableElement> staticNonFinalFields =
+         _task.outputStaticNonFinalFieldLists[librariesMap.outputUnit];
+    if (staticNonFinalFields == null) return const <StaticField>[];
+
+    return staticNonFinalFields
         .map(_buildStaticField)
         .toList(growable: false);
   }