Use FileSystem to read files in SourceLoader and TranslateUri.

pkg/front_end/test/fasta/testing/suite.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.md file.
 
 library fasta.testing.suite;
 
 import 'dart:async' show Future;
 
 import 'dart:io' show File;
 
 import 'dart:convert' show JSON;
 
+import 'package:front_end/physical_file_system.dart';
 import 'package:front_end/src/fasta/testing/validating_instrumentation.dart'
     show ValidatingInstrumentation;
 
 import 'package:front_end/src/fasta/testing/patched_sdk_location.dart';
 
 import 'package:kernel/ast.dart' show Program;
 
 import 'package:testing/testing.dart'
     show
         Chain,
@@ skipping 88 matching lines @@
       Uri sdk = await computePatchedSdk();
       return loadProgramFromBinary(sdk.resolve('platform.dill').toFilePath());
     });
   }
 
   static Future<FastaContext> create(
       Chain suite, Map<String, String> environment) async {
     Uri sdk = await computePatchedSdk();
     Uri vm = computeDartVm(sdk);
     Uri packages = Uri.base.resolve(".packages");
-    TranslateUri uriTranslator = await TranslateUri.parse(packages);
+    TranslateUri uriTranslator =
+        await TranslateUri.parse(PhysicalFileSystem.instance, packages);
     bool strongMode = environment.containsKey(STRONG_MODE);
     bool updateExpectations = environment["updateExpectations"] == "true";
     String astKindString = environment[AST_KIND_INDEX];
     AstKind astKind =
         astKindString == null ? null : AstKind.values[int.parse(astKindString)];
     return new FastaContext(vm, strongMode, updateExpectations, uriTranslator,
         environment.containsKey(ENABLE_FULL_COMPILE), astKind);
   }
 }
 
@@ skipping 41 matching lines @@
   Future<Result<Program>> run(
       TestDescription description, FastaContext 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 = astKind == AstKind.Analyzer
         ? new AnalyzerTarget(dillTarget, context.uriTranslator, strongMode)
-        : new KernelTarget(dillTarget, context.uriTranslator, strongMode);
+        : new KernelTarget(PhysicalFileSystem.instance, dillTarget,
+            context.uriTranslator, strongMode);
 
     Program p;
     try {
       sourceTarget.read(description.uri);
       await dillTarget.writeOutline(null);
       ValidatingInstrumentation instrumentation;
       if (strongMode) {
         instrumentation = new ValidatingInstrumentation();
         await instrumentation.loadExpectations(description.uri);
         sourceTarget.loader.instrumentation = instrumentation;
       }
       p = await sourceTarget.writeOutline(null);
       if (fullCompile) {
         p = await sourceTarget.writeProgram(null);
         instrumentation?.finish();
         if (instrumentation != null && instrumentation.hasProblems) {
           if (updateExpectations) {
             await instrumentation.fixSource(description.uri);
           } else {
             return fail(null, instrumentation.problemsAsString);
           }
         }
       }
     } on InputError catch (e, s) {
       return fail(null, e.error, s);
     }
     return pass(p);
   }
 }