Access parameter data in Annotations, as well as fixed export visibility

pkg/docgen/lib/src/library_helpers.dart

 // Copyright (c) 2014, 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 docgen.library_helpers;
 
 import 'package:logging/logging.dart';
 import 'package:markdown/markdown.dart' as markdown;
 
 import 'exports/source_mirrors.dart';
@@ skipping 11 matching lines @@
   [new markdown.CodeSyntax(r'\[:\s?((?:.|\n)*?)\s?:\]')];
 
 bool get includePrivateMembers {
   if (_includePrivate == null) {
     throw new StateError('includePrivate has not been set');
   }
   return _includePrivate;
 }
 
 void set includePrivateMembers(bool value) {
-  if (_includePrivate != null) {
-    throw new StateError('includePrivate has already been set');
-  }
   if (value == null) throw new ArgumentError('includePrivate cannot be null');
   _includePrivate = value;
 }
 
 bool _includePrivate;
 
 /// Return true if this item and all of its owners are all visible.
 bool isFullChainVisible(Indexable item) {
   return includePrivateMembers || (!item.isPrivate && (item.owner != null ?
       isFullChainVisible(item.owner) : true));
@@ skipping 169 matching lines @@
         append = true;
       }
       index++;
     }
   }
   return tokens;
 }
 
 // HTML escaped version of '<' character.
 const _LESS_THAN = '&lt;';