- Add support for passing data: based URIs as packageConfig to

tests/isolate/scenarios/package_data_uri_spec/package_resolve_test.dart

 // Copyright (c) 2016, 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 'dart:io';
 import 'dart:isolate';
 
 final PACKAGE_URI = "package:foo/bar.dart";
 final PACKAGE_PATH = "file:///no/such/directory/bar.dart";
 
+final PACKAGE_SPEC = """
+# This is the content of a .packages file.
+foo:file:///no/such/directory/
+""";
+
+
 main([args, port]) async {
   if (port != null) {
     testPackageResolution(port);
     return;
   }
+  var data = new Uri.dataFromString(PACKAGE_SPEC);
   var p = new RawReceivePort();
   Isolate.spawnUri(Platform.script,
                    [],
                    p.sendPort,
-                   automaticPackageResolution: true);
+                   packageConfig: data);
   p.handler = (msg) {
     p.close();
     if (msg is! List) {
       print(msg.runtimeType);
       throw "Failure return from spawned isolate:\n\n$msg";
     }
-    var child_pkg_config = Platform.script.resolve(".packages");
-    if (msg[0] != child_pkg_config.toString()) {
+    if (msg[0] != data.toString()) {
       throw "Bad package config in child isolate: ${msg[0]}\n"
-            "Expected: $child_pkg_config";
+            "Expected: $data";
     }
     if (msg[1] != PACKAGE_PATH) {
       throw "Package path not matching: ${msg[1]}";
     }
     print("SUCCESS");
   };
   print("Spawning isolate's package root: ${await Isolate.packageRoot}");
 }
 
 testPackageResolution(port) async {
   try {
     var packageRootStr = Platform.packageRoot;
     var packageConfigStr = Platform.packageConfig;
     var packageConfig = await Isolate.packageConfig;
     var resolvedPkg = await Isolate.resolvePackageUri(Uri.parse(PACKAGE_URI));
     print("Spawned isolate's package root flag: $packageRootStr");
     print("Spawned isolate's package config flag: $packageConfigStr");
     print("Spawned isolate's loaded package config: $packageConfig");
     print("Spawned isolate's resolved package path: $resolvedPkg");
     port.send([packageConfig?.toString(), resolvedPkg?.toString()]);
   } catch (e, s) {
     port.send("$e\n$s\n");
   }
 }