remove docgen source and targets from build

pkg/docgen/lib/src/models/typedef.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.models.typedef;
-
-import '../exports/source_mirrors.dart';
-
-import '../library_helpers.dart';
-
-import 'dummy_mirror.dart';
-import 'library.dart';
-import 'model_helpers.dart';
-import 'generic.dart';
-import 'parameter.dart';
-import 'owned_indexable.dart';
-
-class Typedef extends OwnedIndexable<TypedefMirror> {
-  final String returnType;
-
-  final Map<String, Parameter> parameters;
-
-  /// Generic information about the typedef.
-  final Map<String, Generic> generics;
-
-  /// Returns the [Library] for the given [mirror] if it has already been
-  /// created, else creates it.
-  factory Typedef(TypedefMirror mirror, Library owningLibrary) {
-    var aTypedef = getDocgenObject(mirror, owningLibrary);
-    if (aTypedef is DummyMirror) {
-      aTypedef = new Typedef._(mirror, owningLibrary);
-    }
-    return aTypedef;
-  }
-
-  Typedef._(TypedefMirror mirror, Library owningLibrary)
-      : returnType = getDocgenObject(mirror.referent.returnType).docName,
-        generics = createGenerics(mirror),
-        parameters = createParameters(mirror.referent.parameters,
-            owningLibrary),
-        super(mirror, owningLibrary);
-
-  Map toMap() {
-    var map = {
-      'name': name,
-      'qualifiedName': qualifiedName,
-      'comment': comment,
-      'return': returnType,
-      'parameters': recurseMap(parameters),
-      'annotations': annotations.map((a) => a.toMap()).toList(),
-      'generics': recurseMap(generics)
-    };
-
-    // Typedef is displayed on the library page as a class, so a preview is
-    // added manually
-    var pre = preview;
-    if (pre != null) map['preview'] = pre;
-
-    return map;
-  }
-
-  String get typeName => 'typedef';
-
-  bool isValidMirror(DeclarationMirror mirror) => mirror is TypedefMirror;
-}