Switch pkg packages, pub, and dartdoc to use package: imports.

sdk/lib/_internal/dartdoc/bin/dartdoc.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.
 
 /**
  * To generate docs for a library, run this script with the path to an
  * entrypoint .dart file, like:
  *
  *     $ dart dartdoc.dart foo.dart
  *
  * This will create a "docs" directory with the docs for your libraries. To
  * create these beautiful docs, dartdoc parses your library and every library
  * it imports (recursively). From each library, it parses all classes and
  * members, finds the associated doc comments and builds crosslinked docs from
  * them.
  */
 library dartdoc;
 
 import 'dart:async';
 import 'dart:io';
 
+// TODO(rnystrom): Use "package:" URL (#4968).
 import '../lib/dartdoc.dart';
-
-// TODO(rnystrom): Use "package:" URL (#4968).
-import '../../../../../pkg/args/lib/args.dart';
-import '../../../../../pkg/pathos/lib/path.dart' as path;
+import 'package:args/args.dart';
+import 'package:pathos/path.dart' as path;
 
 /**
  * Run this from the `lib/_internal/dartdoc` directory.
  */
 main() {
   // Need this because ArgParser.getUsage doesn't show command invocation.
   final USAGE = 'Usage dartdoc [options] <entrypoint(s)>\n[options] include:';
 
   final args = new Options().arguments;
 
@@ skipping 213 matching lines @@
       if (dartdoc.totals == 0) {
         exit(1);
       }
     })
     .catchError((e) {
         print('Error: generation failed: ${e.error}');
         exit(1);
     })
     .whenComplete(() => dartdoc.cleanup());
 }