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

pkg/front_end/test/src/incremental/hot_reload_e2e_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.
 
 /// Integration test that runs the incremental compiler, runs the compiled
 /// program, incrementally rebuild portions of the app, and triggers a hot
 /// reload on the running program.
 library front_end.incremental.hot_reload_e2e_test;
 
 import 'dart:async';
@@ skipping 157 matching lines @@
 }
 
 var dartVm = Uri.base.resolve(Platform.resolvedExecutable);
 var sdkRoot = dartVm.resolve("patched_sdk/");
 
 Future<IncrementalKernelGenerator> createIncrementalCompiler(
     String entry, FileSystem fs) {
   var entryUri = Uri.base.resolve(entry);
   var options = new CompilerOptions()
     ..sdkRoot = sdkRoot
+    ..sdkSummary = sdkRoot.resolve('outline.dill')
     ..packagesFileUri = Uri.parse('file:///.packages')
     ..strongMode = false
-    ..compileSdk = true // the incremental generator requires the sdk sources
+    ..dartLibraries = loadDartLibraries()
     ..fileSystem = fs
     ..byteStore = new MemoryByteStore();
   return IncrementalKernelGenerator.newInstance(options, entryUri);
 }
 
+Map<String, Uri> loadDartLibraries() {
+  var libraries = sdkRoot.resolve('lib/libraries.json');
+  var map =
+      JSON.decode(new File.fromUri(libraries).readAsStringSync())['libraries'];
+  var dartLibraries = <String, Uri>{};
+  map.forEach((k, v) => dartLibraries[k] = libraries.resolve(v));
+  return dartLibraries;
+}
+
 Future<bool> rebuild(IncrementalKernelGenerator compiler, Uri outputUri) async {
   compiler.invalidate(Uri.parse("file:///a.dart"));
   compiler.invalidate(Uri.parse("file:///b.dart"));
   var program = (await compiler.computeDelta()).newProgram;
   if (program != null && !program.libraries.isEmpty) {
     await writeProgram(program, outputUri);
     return true;
   }
   return false;
 }
@@ skipping 43 matching lines @@
 
 f() => "$line part2";
 ''';
 
 const sourceB = r'''
 get line => "part1";
 ''';
 
 RegExp observatoryPortRegExp =
     new RegExp("Observatory listening on http://127.0.0.1:\([0-9]*\)/");