Small steps towards deferred loading.

pkg/front_end/lib/src/fasta/import.dart

Index: pkg/front_end/lib/src/fasta/import.dart
diff --git a/pkg/front_end/lib/src/fasta/import.dart b/pkg/front_end/lib/src/fasta/import.dart
index 9c5b205dc0fa8a65b9c9c5fcb6f3a9413a3684f4..3753b7fd99aaa0a43c48d6c9e1c1331cb8c53fe2 100644
--- a/pkg/front_end/lib/src/fasta/import.dart
+++ b/pkg/front_end/lib/src/fasta/import.dart
@@ -17,6 +17,8 @@ class Import {
   /// The library being imported.
   final LibraryBuilder imported;
 
+  final bool deferred;
+
   final String prefix;
 
   final List<Combinator> combinators;
@@ -25,8 +27,8 @@ class Import {
 
   final int prefixCharOffset;
 
-  Import(this.importer, this.imported, this.prefix, this.combinators,
-      this.charOffset, this.prefixCharOffset);
+  Import(this.importer, this.imported, this.deferred, this.prefix,
+      this.combinators, this.charOffset, this.prefixCharOffset);
 
   Uri get fileUri => importer.fileUri;
 
@@ -38,7 +40,8 @@ class Import {
         importer.addToScope(name, member, charOffset, true);
       };
     } else {
-      prefix = new PrefixBuilder(this.prefix, importer, prefixCharOffset);
+      prefix =
+          new PrefixBuilder(this.prefix, deferred, importer, prefixCharOffset);
       add = (String name, Builder member) {
         if (member.isSetter) {
           prefix.exports.setters[name] = member;