Add support for not generating a .dill file.

lib/testing/rasta_chain.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 rasta.testing.rasta_chain;
 
 import 'dart:async' show
     Future;
 
 import 'dart:io' show
     File,
     Platform;
 
 import 'package:kernel/ast.dart' show
     Program;
 
-import 'package:kernel/repository.dart' show
-    Repository;
-
-import 'package:kernel/binary/loader.dart' show
-    BinaryLoader;
-
 import 'package:testing/testing.dart' show
     ChainContext,
     Result,
     Step,
     TestDescription;
 
 import 'package:rasta/src/rastask.dart' show
     Rastask;
 
 import 'package:rasta/src/options.dart' show
@@ skipping 15 matching lines @@
 }
 
 abstract class RastaContext extends ChainContext {
   Rastask get task;
   Uri get temp;
 }
 
 class RastaStep extends Step<TestDescription, Program, RastaContext> {
   final String prefix;
 
-  /// When true, return a copy of the program (by loading it from serialized
-  /// .dill file).
-  final bool reload;
-
-  const RastaStep(this.prefix, {this.reload: false});
+  const RastaStep(this.prefix);
 
   String get name => "rasta";
 
   Future<Result<Program>> run(
       TestDescription description, RastaContext context) async {
     Uri source = description.uri;
     Rastask task = context.task;
 
     assert(task.kernel.isInternalStateConsistent);
 
     print("Rastarizing $source");
     Uri dill = context.temp.resolve(
         "$prefix/${description.shortName}$kernelExtension");
 
     File output = new File.fromUri(dill);
     await output.parent.create(recursive: true);
 
     Options options = new Options(
         source, dill, dependenciesFile: null,
         generateLibrary: false,
-        isVerbose: true, isBatch: false, pattern: null);
+        isVerbose: true, isBatch: false, pattern: null,
+        noOutput: task.globalOptions.noOutput);
 
-    Program program;
     try {
-      program = await task.runOne(options);
+      return pass(await task.runOne(options));
     } catch (e, t) {
       task.kernel.recoverFromCrash();
       return crash(e, t);
     }
-
-    if (reload) {
-      // TODO(ahe): We need to load the serialized form as we otherwise
-      // attempt to modify an unmodifiable list.
-      Repository repository = new Repository();
-      program = new BinaryLoader(repository).loadProgram(dill.toFilePath());
-    }
-
-    return pass(program);
   }
 }