support resolving .packages in FE

pkg/front_end/test/src/incremental/kernel_driver_test.dart

 // Copyright (c) 2017, 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:async';
 
 import 'package:front_end/memory_file_system.dart';
 import 'package:front_end/src/base/performace_logger.dart';
 import 'package:front_end/src/fasta/kernel/utils.dart';
 import 'package:front_end/src/fasta/uri_translator_impl.dart';
 import 'package:front_end/src/incremental/byte_store.dart';
 import 'package:front_end/src/incremental/kernel_driver.dart';
 import 'package:kernel/ast.dart';
 import 'package:kernel/binary/ast_from_binary.dart';
 import 'package:kernel/target/targets.dart';
 import 'package:kernel/text/ast_to_text.dart';
 import 'package:kernel/verifier.dart';
+import 'package:package_config/src/packages_impl.dart';
 import 'package:test/test.dart';
 import 'package:test_reflective_loader/test_reflective_loader.dart';
 
 import 'mock_sdk.dart';
 
 main() {
   defineReflectiveSuite(() {
     defineReflectiveTests(KernelDriverTest);
   });
 }
@@ skipping 566 matching lines @@
     }
     for (var shouldExclude in excludes) {
       expect(libraryUris, isNot(contains(shouldExclude)));
     }
   }
 
   /// Create new [KernelDriver] instance and put it into the [driver] field.
   void _createDriver(
       {Map<String, Uri> packages, KernelDriverFileAddedFn fileAddedFn}) {
     Map<String, Uri> dartLibraries = createSdkFiles(fileSystem);
-    var uriTranslator = new UriTranslatorImpl(dartLibraries, {}, packages);
+    var uriTranslator =
+        new UriTranslatorImpl(dartLibraries, {}, new MapPackages(packages));
     driver = new KernelDriver(
         new PerformanceLog(null),
         fileSystem,
         new MemoryByteStore(),
         uriTranslator,
         new NoneTarget(new TargetFlags(strongMode: true)),
         fileAddedFn: fileAddedFn);
   }
 
   Library _getLibrary(KernelResult result, Uri uri) {
@@ skipping 18 matching lines @@
         .writeLibraryFile(library);
     return buffer.toString();
   }
 
   /// Return the [Uri] for the given Posix [path].
   static Uri _folderUri(String path) {
     if (!path.endsWith('/')) path += '/';
     return Uri.parse('file://$path');
   }
 }