Start pulling pub from its own repo.

sdk/lib/_internal/pub/test/dart2js/source_maps_include_core_libs_test.dart

-// Copyright (c) 2013, the Dart project authors.  Please see the AUTHORS d.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.
-
-import 'package:scheduled_test/scheduled_test.dart';
-
-import '../descriptor.dart' as d;
-import '../test_pub.dart';
-
-main() {
-  initConfig();
-
-  // This test is a bit shaky. Since dart2js is free to inline things, it's
-  // not precise as to which source libraries will actually be referenced in
-  // the source map. But this tries to use a type in the core library
-  // (Duration) and validate that its source ends up in the source map.
-  integration("Dart core libraries are available to source maps", () {
-    d.dir(appPath, [
-      d.appPubspec(),
-      d.dir("web", [
-        d.file("main.dart", "main() => new Duration().toString();"),
-        d.dir("sub", [
-          d.file("main.dart", "main() => new Duration().toString();")
-        ])
-      ])
-    ]).create();
-
-    schedulePub(args: ["build", "--mode", "debug"],
-        output: new RegExp(r'Built \d+ files to "build".'),
-        exitCode: 0);
-
-    d.dir(appPath, [
-      d.dir("build", [
-        d.dir("web", [
-          d.matcherFile("main.dart.js.map",
-              contains(r"packages/$sdk/lib/core/duration.dart")),
-          d.dir("sub", [
-            d.matcherFile("main.dart.js.map",
-                contains(r"../packages/$sdk/lib/core/duration.dart"))
-          ]),
-          d.dir("packages", [
-            d.dir(r"$sdk", [
-              d.dir("lib", [
-                d.dir(r"core", [
-                  d.matcherFile("duration.dart",
-                      contains("class Duration"))
-                ])
-              ])
-            ])
-          ])
-        ])
-      ])
-    ]).validate();
-  });
-}