Use FileSystem to read files in SourceLoader and TranslateUri.

pkg/kernel/test/interpreter/suite.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.md file.
 
 library test.kernel.closures.suite;
 
 import 'dart:async' show Future;
 
 import 'dart:io' show File;
 
+import 'package:front_end/physical_file_system.dart';
 import 'package:testing/testing.dart'
     show Chain, ChainContext, Result, Step, TestDescription, runMe;
 
 import 'package:kernel/ast.dart' show Program, Library;
 
 import 'package:front_end/src/fasta/testing/kernel_chain.dart' show runDiff;
 
 import 'package:front_end/src/fasta/ticker.dart' show Ticker;
 
 import 'package:front_end/src/fasta/dill/dill_target.dart' show DillTarget;
@@ skipping 31 matching lines @@
 
   Future<Program> loadPlatform() async {
     Uri sdk = await computePatchedSdk();
     return loadProgramFromBinary(sdk.resolve('platform.dill').toFilePath());
   }
 
   static Future<InterpreterContext> create(
       Chain suite, Map<String, String> environment) async {
     Uri packages = Uri.base.resolve(".packages");
     bool strongMode = environment.containsKey(STRONG_MODE);
-    TranslateUri uriTranslator = await TranslateUri.parse(packages);
+    TranslateUri uriTranslator =
+        await TranslateUri.parse(PhysicalFileSystem.instance, packages);
     return new InterpreterContext(strongMode, uriTranslator);
   }
 }
 
 class FastaCompile extends Step<TestDescription, Program, InterpreterContext> {
   const FastaCompile();
 
   String get name => "fasta compile";
 
   Future<Result<Program>> run(
       TestDescription description, InterpreterContext context) async {
     Program platform = await context.loadPlatform();
     Ticker ticker = new Ticker();
     DillTarget dillTarget = new DillTarget(ticker, context.uriTranslator);
     dillTarget.loader
       ..input = Uri.parse("org.dartlang:platform") // Make up a name.
       ..setProgram(platform);
-    KernelTarget sourceTarget =
-        new KernelTarget(dillTarget, context.uriTranslator, context.strongMode);
+    KernelTarget sourceTarget = new KernelTarget(PhysicalFileSystem.instance,
+        dillTarget, context.uriTranslator, context.strongMode);
 
     Program p;
     try {
       sourceTarget.read(description.uri);
       await dillTarget.writeOutline(null);
       await sourceTarget.writeOutline(null);
       p = await sourceTarget.writeProgram(null);
     } on InputError catch (e, s) {
       return fail(null, e.error, s);
     }
@@ skipping 55 matching lines @@
   final Uri uri;
 
   /// Evaluated program log.
   final String log;
 
   EvaluationLog(this.uri, this.log);
 }
 
 main(List<String> arguments) =>
     runMe(arguments, InterpreterContext.create, "testing.json");