dart2js: fix dependency tracking for deferred loading when types are only used

tests/compiler/dart2js_extra/23853_test.dart

+// Copyright (c) 2015, the Dart project authors.  Please see the AUTHORS file
+// for details. All rights reserved. Use of this source code is governed by a
+// BSD-style license that can be found in the LICENSE file.
+
+// Regression for issue 23853: if a type was mainly used in a deferred library,
+// but could be used in a generic type in the main library
+
+import 'import_a_23853.dart';

[floitsch, 2015/07/17 09:22:25]

Use descriptive file-names. You can still mention the bug-number here, though.

[Siggi Cherem (dart-lang), 2015/07/17 15:34:49]

Done.

+import 'import_b_23853.dart' deferred as b;
+
+class TypeLiteral<T> {
+  Type get type => T;
+}
+
+main() {
+  // This line failed with a runtime error prior to the bug fix:
+  new TypeLiteral<A<Object>>().type;
+
+  b.loadLibrary().then((_) => b.createA());
+}