Revert "Switch FE to use the libraries.json format."

pkg/front_end/test/incremental_kernel_generator_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/compiler_options.dart';
 import 'package:front_end/incremental_kernel_generator.dart';
 import 'package:front_end/memory_file_system.dart';
 import 'package:front_end/src/incremental/byte_store.dart';
@@ skipping 18 matching lines @@
 
   /// The used file watcher.
   WatchUsedFilesFn watchFn = (uri, used) {};
 
   /// The object under test.
   IncrementalKernelGeneratorImpl incrementalKernelGenerator;
 
   /// Compute the initial [Program] for the given [entryPoint].
   Future<Program> getInitialState(Uri entryPoint,
       {bool setPackages: true}) async {
-    createSdkFiles(fileSystem);
+    Map<String, Uri> dartLibraries = createSdkFiles(fileSystem);
     // TODO(scheglov) Builder the SDK kernel and set it into the options.
 
+    // TODO(scheglov) Make `.packages` file optional.
+
     var compilerOptions = new CompilerOptions()
       ..fileSystem = fileSystem
       ..byteStore = new MemoryByteStore()
 //      ..logger = new PerformanceLog(stdout)
       ..strongMode = true
       ..chaseDependencies = true
-      ..librariesSpecificationUri = Uri.parse('file:///sdk/lib/libraries.json');
+      ..dartLibraries = dartLibraries;
 
     if (setPackages) {
       compilerOptions.packagesFileUri = Uri.parse('file:///test/.packages');
     }
     incrementalKernelGenerator = await IncrementalKernelGenerator
         .newInstance(compilerOptions, entryPoint, watch: watchFn);
     return (await incrementalKernelGenerator.computeDelta()).newProgram;
   }
 
   test_compile_chain() async {
@@ skipping 319 matching lines @@
     throw fail('No library found with URI "$uri"');
   }
 
   String _getLibraryText(Library library) {
     StringBuffer buffer = new StringBuffer();
     new Printer(buffer, syntheticNames: new NameSystem())
         .writeLibraryFile(library);
     return buffer.toString();
   }
 }