remove docgen source and targets from build

pkg/docgen/lib/src/models/dummy_mirror.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.dummy_mirror;
-
-import '../exports/mirrors_util.dart' as dart2js_util;
-import '../exports/source_mirrors.dart';
-
-import '../library_helpers.dart';
-
-import 'indexable.dart';
-import 'model_helpers.dart';
-
-/// For types that we do not explicitly create or have not yet created in our
-/// entity map (like core types).
-class DummyMirror implements Indexable {
-  final DeclarationMirror mirror;
-  /// The library that contains this element, if any. Used as a hint to help
-  /// determine which object we're referring to when looking up this mirror in
-  /// our map.
-  final Indexable owner;
-
-  DummyMirror(this.mirror, [this.owner]);
-
-  String get docName {
-    if (mirror is LibraryMirror) {
-      return getLibraryDocName(mirror);
-    }
-    var mirrorOwner = mirror.owner;
-    if (mirrorOwner == null) return dart2js_util.qualifiedNameOf(mirror);
-    var simpleName = dart2js_util.nameOf(mirror);
-    if (mirror is MethodMirror && (mirror as MethodMirror).isConstructor) {
-      // We name constructors specially -- repeating the class name and a
-      // "-" to separate the constructor from its name (if any).
-      simpleName = '${dart2js_util.nameOf(mirrorOwner)}-$simpleName';
-    }
-    return getDocgenObject(mirrorOwner, owner).docName + '.' +
-        simpleName;
-  }
-
-  bool get isPrivate => mirror.isPrivate;
-
-  String get packageName {
-    var libMirror = _getOwningLibraryFromMirror(mirror);
-    if (libMirror != null) {
-      return getPackageName(libMirror);
-    }
-    return '';
-  }
-
-  String get packagePrefix => packageName == null || packageName.isEmpty ?
-      '' : '$packageName/';
-
-  // This is a known incomplete implementation of Indexable
-  // overriding noSuchMethod to remove static warnings
-  noSuchMethod(Invocation invocation) {
-    throw new UnimplementedError(invocation.memberName.toString());
-  }
-}
-
-LibraryMirror _getOwningLibraryFromMirror(DeclarationMirror mirror) {
-  if (mirror == null) return null;
-  if (mirror is LibraryMirror) return mirror;
-  return _getOwningLibraryFromMirror(mirror.owner);
-}