dart2js: The name of a library without a library declaration is the empty string.

sdk/lib/_internal/compiler/implementation/elements/modelx.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 elements.modelx;
 
 import 'elements.dart';
 import '../../compiler.dart' as api;
 import '../tree/tree.dart';
 import '../util/util.dart';
@@ skipping 916 matching lines @@
     return localScope.values.where((Element element) {
       // At this point [localScope] only contains members so we don't need
       // to check for foreign or prefix elements.
       return !isPrivateName(element.name);
     });
   }
 
   bool hasLibraryName() => libraryTag != null;
 
   /**
+   * Returns the library name, which is either the name given in the library tag
+   * or the empty string if there is no library tag.
+   */
+  String getLibraryName() {
+    if (libraryTag == null) return '';
+    return libraryTag.name.toString();
+  }
+
+  /**
    * Returns the library name (as defined by the library tag) or for script
    * (which have no library tag) the script file name. The latter case is used
    * to private 'library name' for scripts to use for instance in dartdoc.
    */
   String getLibraryOrScriptName() {
     if (libraryTag != null) {
       return libraryTag.name.toString();
     } else {
       // Use the file name as script name.
       String path = canonicalUri.path;
@@ skipping 1407 matching lines @@
 
   MetadataAnnotation ensureResolved(Compiler compiler) {
     if (resolutionState == STATE_NOT_STARTED) {
       compiler.resolver.resolveMetadataAnnotation(this);
     }
     return this;
   }
 
   String toString() => 'MetadataAnnotation($value, $resolutionState)';
 }