js: fix core.Object, output order, static const fields

lib/src/info.dart

Index: lib/src/info.dart
diff --git a/lib/src/info.dart b/lib/src/info.dart
index 80413fdad92524f3a2bd3aab992a2d3b0afc0139..6947db6dfa90fa709f61c1daede8885fe1e2f79c 100644
--- a/lib/src/info.dart
+++ b/lib/src/info.dart
@@ -47,6 +47,23 @@ class LibraryInfo {
         name = utils.canonicalLibraryName(library);
 }
 
+class LibraryUnit {
+  final CompilationUnit library;
+  final List<CompilationUnit> parts;
+
+  LibraryUnit(this.library, this.parts);
+
+  Iterable<CompilationUnit> get libraryThenParts sync* {
+    yield library;
+    yield* parts;
+  }
+
+  Iterable<CompilationUnit> get partsThenLibrary sync* {
+    yield* parts;
+    yield library;
+  }
+}
+
 // The abstract type of coercions mapping one type to another.
 // This class also exposes static builder functions which
 // check for errors and reduce redundant coercions to the identity.