Implement LibraryMirror.metadata.

dart/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 263 matching lines @@
         libraryDependencies.addLast(import);
       } else if (tag.isExport) {
         tagState = checkTag(TagState.IMPORT_OR_EXPORT, tag);
         libraryDependencies.addLast(tag);
       } else if (tag.isLibraryName) {
         tagState = checkTag(TagState.LIBRARY, tag);
         if (library.libraryTag != null) {
           compiler.cancel("duplicated library declaration", node: tag);
         } else {
           library.libraryTag = tag;
+          for (Link link = tag.metadata; !link.isEmpty; link = link.tail) {
+            library.addMetadata(link.head);
+          }
         }
         checkDuplicatedLibraryName(library);
       } else if (tag.isPart) {
         Part part = tag;
         StringNode uri = part.uri;
         Uri resolvedUri = base.resolve(uri.dartString.slowToString());
         tagState = checkTag(TagState.SOURCE, part);
         scanPart(part, resolvedUri, library);
       } else {
         compiler.internalError("Unhandled library tag.", node: tag);
@@ skipping 537 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();
   }
 }