Format all files under tools and utils directory.

tools/yaml2json.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:io' show File, exit, stderr;
 
 import 'dart:isolate' show RawReceivePort;
 
 import 'dart:convert' show JsonEncoder;
 
 import 'package:yaml/yaml.dart' show loadYaml;
 
 main(List<String> arguments) async {
   var port = new RawReceivePort();
   if (arguments.length != 2) {
     stderr.writeln("Usage: yaml2json.dart input.yaml output.json");
     exit(1);
   }
   Uri input = Uri.base.resolve(arguments[0]);
   Uri output = Uri.base.resolve(arguments[1]);
   var yaml = loadYaml(await new File.fromUri(input).readAsString());
-  await new File.fromUri(output).writeAsString(
-      const JsonEncoder.withIndent("  ").convert(yaml));
+  await new File.fromUri(output)
+      .writeAsString(const JsonEncoder.withIndent("  ").convert(yaml));
   port.close();
 }