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

sdk/lib/_internal/compiler/implementation/library_loader.dart

 // Copyright (c) 2012, 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.
 
 part of dart2js;
 
 /**
  * [CompilerTask] for loading libraries and setting up the import/export scopes.
  *
  * The library loader uses four different kinds of URIs in different parts of
@@ skipping 321 matching lines @@
         return compiler.withCurrentElement(library, () {
           return registerLibraryFromTag(handler, library, tag);
         });
       });
     });
   }
 
   void checkDuplicatedLibraryName(LibraryElement library) {
     LibraryName tag = library.libraryTag;
     if (tag != null) {
-      String name = library.getLibraryOrScriptName();
+      String name = library.getLibraryName();
       LibraryElement existing =
           libraryNames.putIfAbsent(name, () => library);
       if (!identical(existing, library)) {
         Uri uri = library.entryCompilationUnit.script.uri;
         compiler.reportMessage(
             compiler.spanFromSpannable(tag.name, uri),
             MessageKind.DUPLICATED_LIBRARY_NAME.error({'libraryName': name}),
             api.Diagnostic.WARNING);
         Uri existingUri = existing.entryCompilationUnit.script.uri;
         compiler.reportMessage(
@@ skipping 563 matching lines @@
   }
 
   /**
    * Registers all top-level entities of [library] as starting point for the
    * fixed-point computation of the import/export scopes.
    */
   void registerLibraryExports(LibraryElement library) {
     nodeMap[library].registerInitialExports();
   }
 }