Use deferred loading for message catalogs.

pkg/intl/lib/generate_localized.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.
 
 /**
  * This provides utilities for generating localized versions of
  * messages. It does not stand alone, but expects to be given
  * TranslatedMessage objects and generate code for a particular locale
  * based on them.
  *
@@ skipping 161 matching lines @@
 /**
  * This section generates the messages_all.dart file based on the list of
  * [allLocales].
  */
 String generateMainImportFile() {
   var output = new StringBuffer();
   output.write(mainPrologue);
   for (var locale in allLocales) {
     var baseFile = '${generatedFilePrefix}messages_$locale.dart';
     var file = importForGeneratedFile(baseFile);
-    // TODO(alanknight): Restore this once deferred loading works in dartj2s.
-    // Issue 12824
-    //    output.write("@${_deferredName(locale)}\n");
-    output.write("import '$file' as ${_libraryName(locale)};\n");
+    output.write("import '$file' deferred as ${_libraryName(locale)};\n");
   }
   output.write("\n");
-  // Issue 12824
-  //for (var locale in allLocales) {
-  //  output.write("const ${_deferredName(locale)} = const DeferredLibrary");
-  //  output.write("('${_libraryName(locale)}');\n");
-  //}
-  //output.write("\nconst deferredLibraries = const {\n");
-  //for (var locale in allLocales) {
-  //  output.write("  '$locale' : ${_deferredName(locale)},\n");
-  //}
-  //output.write("};\n");
+  output.write("\nMap<String, Function> _deferredLibraries = {\n");
+  for (var locale in allLocales) {
+    output.write("  '$locale' : () => ${_libraryName(locale)}.loadLibrary(),\n");
+  }
+  output.write("};\n");
   output.write(
     "\nMessageLookupByLibrary _findExact(localeName) {\n"
     "  switch (localeName) {\n");
   for (var rawLocale in allLocales) {
     var locale = Intl.canonicalizedLocale(rawLocale);
     output.write(
         "    case '$locale' : return ${_libraryName(locale)}.messages;\n");
   }
   output.write(closing);
   return output.toString();
@@ skipping 23 matching lines @@
  * Constant string used in [generateMainImportFile] as the end of the file.
  */
 const closing = """
     default: return null;
   }
 }
 
 /** User programs should call this before using [localeName] for messages.*/
 Future initializeMessages(String localeName) {
   initializeInternalMessageLookup(() => new CompositeMessageLookup());
-  messageLookup.addLocale(localeName, _findGeneratedMessagesFor);
-  // TODO(alanknight): Restore once Issue 12824 is fixed.
-  // var lib = deferredLibraries[localeName];
-  // return lib == null ? new Future.value(false) : lib.load();
-  return new Future.value(true);
+  var lib = _deferredLibraries[Intl.canonicalizedLocale(localeName)];
+  var load = lib == null ? new Future.value(false) : lib();
+  return load.then((_) => 
+      messageLookup.addLocale(localeName, _findGeneratedMessagesFor));
 }
 
 MessageLookupByLibrary _findGeneratedMessagesFor(locale) {
   var actualLocale = Intl.verifiedLocale(locale, (x) => _findExact(x) != null,
       onFailure: (_) => null);
   if (actualLocale == null) return null;
   return _findExact(actualLocale);
 }
 """;