Refactor test servers to make them less global.

test/get/hosted/avoid_network_requests_test.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.
 
 import 'package:scheduled_test/scheduled_test.dart';
 
 import '../../descriptor.dart' as d;
 import '../../test_pub.dart';
 
 main() {
   integration('only requests versions that are needed during solving', () {
     servePackages((builder) {
       builder.serve("foo", "1.0.0");
       builder.serve("foo", "1.1.0");
       builder.serve("foo", "1.2.0");
       builder.serve("bar", "1.0.0");
       builder.serve("bar", "1.1.0");
       builder.serve("bar", "1.2.0");
     });
 
     d.appDir({
       "foo": "any"
     }).create();
 
     // Get once so it gets cached.
     pubGet();
 
     // Clear the cache. We don't care about anything that was served during
     // the initial get.
-    getRequestedPaths();
+    globalServer.clearRequestedPaths();
 
     // Add "bar" to the dependencies.
     d.appDir({
       "foo": "any",
       "bar": "any"
     }).create();
 
     // Run the solver again.
     pubGet();
 
     d.packagesDir({
       "foo": "1.2.0",
       "bar": "1.2.0"
     }).validate();
 
     // The get should not have done any network requests since the lock file is
     // up to date.
-    getRequestedPaths().then((paths) {
+    globalServer.requestedPaths.then((paths) {
       expect(paths, unorderedEquals([
         // Bar should be requested because it's new, but not foo.
         "api/packages/bar",
         // Need to download it.
         "packages/bar/versions/1.2.0.tar.gz"
       ]));
     });
   });
 }