Add a way to use shared CanonicalName root to deserialize Program.

pkg/front_end/lib/kernel_generator.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.
 
 /// Defines the front-end API for converting source code to Dart Kernel objects.
 library front_end.kernel_generator;
 
 import 'compiler_options.dart';
 import 'dart:async' show Future;
 import 'dart:async';
@@ skipping 36 matching lines @@
     return report("Entry-point file not found: $source");
   }
 
   if (!await validateOptions(options)) return null;
 
   try {
     TranslateUri uriTranslator = await TranslateUri.parse(
         PhysicalFileSystem.instance, null, options.packagesFileUri);
 
     var dillTarget =
-        new DillTarget(new Ticker(isVerbose: false), uriTranslator);
+        new DillTarget(null, new Ticker(isVerbose: false), uriTranslator);
     var summary = options.sdkSummary;
     if (summary != null) dillTarget.read(summary);
 
     var kernelTarget = new KernelTarget(
         options.fileSystem, dillTarget, uriTranslator, options.strongMode);
     kernelTarget.read(source);
 
     await dillTarget.writeOutline(null);
     await kernelTarget.writeOutline(null);
     Program program = await kernelTarget.writeProgram(null);
@@ skipping 48 matching lines @@
 /// TODO(paulberry): would it be better to define a data type in kernel to
 /// represent a bundle of all the libraries in a given build unit?
 ///
 /// TODO(paulberry): does additional information need to be output to allow the
 /// caller to match up referenced elements to the summary files they were
 /// obtained from?
 Future<Program> kernelForBuildUnit(
     List<Uri> sources, CompilerOptions options) async {
   throw new UnimplementedError("kernel for build-unit is not implemented");
 }