Use FileSystem to read files in SourceLoader and TranslateUri.

pkg/front_end/lib/src/fasta/fasta.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.
 
 library fasta;
 
 import 'dart:async' show Future;
 
 import 'dart:convert' show JSON;
 
 import 'dart:io' show BytesBuilder, Directory, File, exitCode;
 
+import 'package:front_end/physical_file_system.dart';
 import 'package:kernel/binary/ast_to_binary.dart'
     show LibraryFilteringBinaryPrinter;
 
 import 'package:kernel/kernel.dart' show Program, Library;
 
 import 'package:kernel/target/targets.dart' show Target, TargetFlags, getTarget;
 
 import 'compiler_command_line.dart' show CompilerCommandLine;
 
 import 'compiler_context.dart' show CompilerContext;
@@ skipping 87 matching lines @@
 
   CompileTask(this.c, this.ticker);
 
   DillTarget createDillTarget(TranslateUri uriTranslator) {
     return new DillTarget(ticker, uriTranslator);
   }
 
   KernelTarget createKernelTarget(
       DillTarget dillTarget, TranslateUri uriTranslator, bool strongMode) {
     return new KernelTarget(
-        dillTarget, uriTranslator, strongMode, c.uriToSource);
+        c.fileSystem, dillTarget, uriTranslator, strongMode, c.uriToSource);
   }
 
   Future<KernelTarget> buildOutline([Uri output]) async {
-    TranslateUri uriTranslator =
-        await TranslateUri.parse(c.options.sdk, c.options.packages);
+    TranslateUri uriTranslator = await TranslateUri.parse(
+        c.fileSystem, c.options.sdk, c.options.packages);
     ticker.logMs("Read packages file");
     DillTarget dillTarget = createDillTarget(uriTranslator);
     KernelTarget kernelTarget =
         createKernelTarget(dillTarget, uriTranslator, c.options.strongMode);
     if (c.options.strongMode) {
       print("Note: strong mode support is preliminary and may not work.");
     }
     Uri platform = c.options.platform;
     if (platform != null) {
       dillTarget.read(platform);
@@ skipping 32 matching lines @@
       return new CompilationResult.error(
           formatUnexpected(fileName, -1, "No such file."));
     }
     if (!await new Directory.fromUri(patchedSdk).exists()) {
       return new CompilationResult.error(
           formatUnexpected(patchedSdk, -1, "Patched sdk directory not found."));
     }
 
     Program program;
     try {
-      TranslateUri uriTranslator = await TranslateUri.parse(null, packages);
+      TranslateUri uriTranslator =
+          await TranslateUri.parse(PhysicalFileSystem.instance, null, packages);
       final Ticker ticker = new Ticker(isVerbose: verbose);
       final DillTarget dillTarget = new DillTarget(ticker, uriTranslator);
       dillTarget.read(patchedSdk.resolve('platform.dill'));
-      final KernelTarget kernelTarget =
-          new KernelTarget(dillTarget, uriTranslator, strongMode);
+      final KernelTarget kernelTarget = new KernelTarget(
+          PhysicalFileSystem.instance, dillTarget, uriTranslator, strongMode);
       kernelTarget.read(fileName);
       await dillTarget.writeOutline(null);
       program = await kernelTarget.writeOutline(null);
       program = await kernelTarget.writeProgram(null);
       if (kernelTarget.errors.isNotEmpty) {
         return new CompilationResult.errors(kernelTarget.errors
             .map((err) => err.toString())
             .toList(growable: false));
       }
     } on InputError catch (e) {
@@ skipping 44 matching lines @@
     Iterable<Uri> extraDependencies,
     bool verbose: false}) async {
   Ticker ticker = new Ticker(isVerbose: verbose);
   await CompilerCommandLine.withGlobalOptions("", [""],
       (CompilerContext c) async {
     c.options.options["--packages"] = packages;
     if (verbose) {
       c.options.options["--verbose"] = true;
     }
 
-    TranslateUri uriTranslator =
-        await TranslateUri.parse(c.options.sdk, c.options.packages);
+    TranslateUri uriTranslator = await TranslateUri.parse(
+        c.fileSystem, c.options.sdk, c.options.packages);
     ticker.logMs("Read packages file");
     DillTarget dillTarget = new DillTarget(ticker, uriTranslator)
       ..read(platform);
-    KernelTarget kernelTarget =
-        new KernelTarget(dillTarget, uriTranslator, false, c.uriToSource);
+    KernelTarget kernelTarget = new KernelTarget(PhysicalFileSystem.instance,
+        dillTarget, uriTranslator, false, c.uriToSource);
 
     kernelTarget.read(script);
     await dillTarget.writeOutline(null);
     await kernelTarget.loader.buildOutlines();
     await kernelTarget.writeDepsFile(output, depsFile,
         extraDependencies: extraDependencies);
   });
 }
 
 // TODO(ahe): https://github.com/dart-lang/sdk/issues/28316
 class ByteSink implements Sink<List<int>> {
   final BytesBuilder builder = new BytesBuilder();
 
   void add(List<int> data) {
     builder.add(data);
   }
 
   void close() {
     // Nothing to do.
   }
 }