Start pulling pub from its own repo.

sdk/lib/_internal/pub/test/dart2js/environment_constant_test.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.
-
-import 'package:scheduled_test/scheduled_test.dart';
-
-import '../descriptor.dart' as d;
-import '../serve/utils.dart';
-import '../test_pub.dart';
-
-main() {
-  initConfig();
-  group("passes environment constants to dart2js", () {
-    setUp(() {
-      // Dart2js can take a long time to compile dart code, so we increase the
-      // timeout to cope with that.
-      currentSchedule.timeout *= 3;
-
-      d.dir(appPath, [
-        d.appPubspec(),
-        d.dir('web', [
-          d.file('file.dart',
-              'void main() => print(const String.fromEnvironment("name"));')
-        ])
-      ]).create();
-    });
-
-    integration('from "pub build"', () {
-      schedulePub(args: ["build", "--define", "name=fblthp"],
-          output: new RegExp(r'Built 1 file to "build".'));
-
-      d.dir(appPath, [
-        d.dir('build', [
-          d.dir('web', [
-            d.matcherFile('file.dart.js', contains('fblthp')),
-          ])
-        ])
-      ]).validate();
-    });
-
-    integration('from "pub serve"', () {
-      pubServe(args: ["--define", "name=fblthp"]);
-      requestShouldSucceed("file.dart.js", contains("fblthp"));
-      endPubServe();
-    });
-
-    integration('which takes precedence over the pubspec', () {
-      d.dir(appPath, [
-        d.pubspec({
-          "name": "myapp",
-          "transformers": [
-            {"\$dart2js": {"environment": {"name": "slartibartfast"}}}
-          ]
-        })
-      ]).create();
-
-      pubServe(args: ["--define", "name=fblthp"]);
-      requestShouldSucceed("file.dart.js", allOf([
-        contains("fblthp"),
-        isNot(contains("slartibartfast"))
-      ]));
-      endPubServe();
-    });
-  });
-}