Recompute librariesByName after loading a deferred library.

sdk/lib/_internal/compiler/js_lib/js_helper.dart

 // Copyright (c) 2013, 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.
 
 library _js_helper;
 
 import 'shared/embedded_names.dart' show
     ALL_CLASSES,
     GET_ISOLATE_TAG,
     INTERCEPTED_NAMES,
@@ skipping 3239 matching lines @@
 
 typedef Future<Null> LoadLibraryFunctionType();
 
 LoadLibraryFunctionType _loadLibraryWrapper(String loadId) {
   return () => loadDeferredLibrary(loadId);
 }
 
 final Map<String, Future<Null>> _loadingLibraries = <String, Future<Null>>{};
 final Set<String> _loadedLibraries = new Set<String>();
 
+typedef void DeferredLoadCallback();
+
+// Function that will be called every time a new deferred import is loaded.
+DeferredLoadCallback deferredLoadHook;
+
 Future<Null> loadDeferredLibrary(String loadId) {
   // For each loadId there is a list of hunk-uris to load, and a corresponding
   // list of hashes. These are stored in the app-global scope.
   List<String> uris = JS('JSExtendableArray|Null',
       'init.deferredLibraryUris[#]', loadId);
   List<String> hashes = JS('JSExtendableArray|Null',
       'init.deferredLibraryHashes[#]', loadId);
   if (uris == null) return new Future.value(null);
   // The indices into `uris` and `hashes` that we want to load.
   List<int> indices = new List.generate(uris.length, (i) => i);
   return Future.wait(indices
       // Filter away indices for hunks that have already been loaded.
       .where((int i) => !JS('bool','init.isHunkLoaded(#)', hashes[i]))
       // Load the rest.
       .map((int i) => _loadHunk(uris[i]))).then((_) {
     // Now all hunks have been loaded, we call all their initializers
     for (String hash in hashes) {
       // TODO(floitsch): Replace unsafe access to embedded global.
       JS('void', 'init.initializeLoadedHunk(#)', hash);
     }
-    _loadedLibraries.add(loadId);
+    bool updated = _loadedLibraries.add(loadId);
+    if (updated && deferredLoadHook != null) {
+      deferredLoadHook();
+    }
   });
 }
 
 Future<Null> _loadHunk(String hunkName) {
   // TODO(ahe): Validate libraryName.  Kasper points out that you want
   // to be able to experiment with the effect of toggling @DeferLoad,
   // so perhaps we should silently ignore "bad" library names.
   Future<Null> future = _loadingLibraries[hunkName];
   if (future != null) {
     return future.then((_) => null);
@@ skipping 94 matching lines @@
   throw new MainError("No top-level function named 'main'.");
 }
 
 void badMain() {
   throw new MainError("'main' is not a function.");
 }
 
 void mainHasTooManyParameters() {
   throw new MainError("'main' expects too many parameters.");
 }