Parse new library syntax.

dart/pkg/dartdoc/lib/src/mirrors/dart2js_mirror.dart

Index: dart/pkg/dartdoc/lib/src/mirrors/dart2js_mirror.dart
diff --git a/dart/pkg/dartdoc/lib/src/mirrors/dart2js_mirror.dart b/dart/pkg/dartdoc/lib/src/mirrors/dart2js_mirror.dart
index 24ce9625ffbe30ee7ec4200ee897f35e8f7745fc..4a4da301622ccb4e71e0b0bb4c1ddb11fb38929c 100644
--- a/dart/pkg/dartdoc/lib/src/mirrors/dart2js_mirror.dart
+++ b/dart/pkg/dartdoc/lib/src/mirrors/dart2js_mirror.dart
@@ -492,7 +492,13 @@ class Dart2JsLibraryMirror extends Dart2JsObjectMirror
    */
   String get simpleName {
     if (_library.libraryTag !== null) {
-      return _library.libraryTag.argument.dartString.slowToString();
+      // TODO(ahe): Remove StringNode check when old syntax is removed.
+      StringNode name = _library.libraryTag.name.asStringNode();
+      if (name !== null) {
+        return name.dartString.slowToString();
+      } else {
+        return _library.libraryTag.name.toString();
+      }
     } else {
       // Use the file name as script name.
       String path = _library.uri.path;