Introduces the new syntax for deferred loading

tests/compiler/dart2js/unparser_test.dart

Index: tests/compiler/dart2js/unparser_test.dart
diff --git a/tests/compiler/dart2js/unparser_test.dart b/tests/compiler/dart2js/unparser_test.dart
index 540976800600f6e4719d28de52685d4322d50cf3..21fe65dfdefa4bac8c643ef71b740666293043f3 100644
--- a/tests/compiler/dart2js/unparser_test.dart
+++ b/tests/compiler/dart2js/unparser_test.dart
@@ -203,6 +203,13 @@ testCombinators() {
   testUnparseTopLevelWithMetadata('export "søhest" hide a,show hide a,show;');
 }
 
+testDeferredImport() {
+  testUnparseTopLevelWithMetadata('import "lib.dart" as a;');
+  testUnparseTopLevelWithMetadata('import "lib.dart" deferred as a;');
+  testUnparseTopLevelWithMetadata('import "lib.dart" deferred as a show b;');
+  testUnparseTopLevelWithMetadata('import "lib.dart" deferred as a hide b;');
+}
+
 testUnparseMemberAndAsMemberOfFoo(String code) {
   testUnparseMember(code);
   testUnparseTopLevelWithMetadata('class Foo{$code}');
@@ -380,6 +387,7 @@ main() {
   testPart();
   testPartOf();
   testCombinators();
+  testDeferredImport();
   testRedirectingFactoryConstructors();
   testClassDeclarations();
   testMixinApplications();