Start pulling pub from its own repo.

sdk/lib/_internal/pub/test/build/copies_browser_js_next_to_entrypoints_test.dart

-// Copyright (c) 2013, 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 '../test_pub.dart';
-import 'utils.dart';
-
-main() {
-  initConfig();
-
-  integration("compiles dart.js and interop.js next to entrypoints", () {
-    // Dart2js can take a long time to compile dart code, so we increase the
-    // timeout to cope with that.
-    currentSchedule.timeout *= 3;
-
-    serveBrowserPackage();
-
-    d.dir(appPath, [
-      d.appPubspec({"browser": "1.0.0"}),
-      d.dir('foo', [
-        d.file('file.dart', 'void main() => print("hello");'),
-        d.dir('subdir', [
-          d.file('subfile.dart', 'void main() => print("subhello");')
-        ])
-      ]),
-      d.dir('web', [
-        d.file('file.dart', 'void main() => print("hello");'),
-        d.dir('subweb', [
-          d.file('subfile.dart', 'void main() => print("subhello");')
-        ])
-      ])
-    ]).create();
-
-    pubGet();
-
-    schedulePub(args: ["build", "foo", "web"],
-        output: new RegExp(r'Built 12 files to "build".'));
-
-    d.dir(appPath, [
-      d.dir('build', [
-        d.dir('foo', [
-          d.matcherFile('file.dart.js', isNot(isEmpty)),
-          d.dir('packages', [d.dir('browser', [
-            d.file('dart.js', 'contents of dart.js'),
-            d.file('interop.js', 'contents of interop.js')
-          ])]),
-          d.dir('subdir', [
-            d.dir('packages', [d.dir('browser', [
-              d.file('dart.js', 'contents of dart.js'),
-              d.file('interop.js', 'contents of interop.js')
-            ])]),
-            d.matcherFile('subfile.dart.js', isNot(isEmpty)),
-          ])
-        ]),
-        d.dir('web', [
-          d.matcherFile('file.dart.js', isNot(isEmpty)),
-          d.dir('packages', [d.dir('browser', [
-            d.file('dart.js', 'contents of dart.js'),
-            d.file('interop.js', 'contents of interop.js')
-          ])]),
-          d.dir('subweb', [
-            d.dir('packages', [d.dir('browser', [
-              d.file('dart.js', 'contents of dart.js'),
-              d.file('interop.js', 'contents of interop.js')
-            ])]),
-            d.matcherFile('subfile.dart.js', isNot(isEmpty))
-          ])
-        ])
-      ])
-    ]).validate();
-  });
-}