Add support for passing in precompiled JS.

lib/src/runner/configuration/args.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.
 
 import 'dart:io';
 
 import 'package:args/args.dart';
 import 'package:boolean_selector/boolean_selector.dart';
 
 import '../../backend/test_platform.dart';
@@ skipping 100 matching lines @@
   parser.addOption("dart2js-args",
       help: 'Extra arguments to pass to dart2js.',
       allowMultiple: true, hide: true);
   parser.addOption("total-shards",
       help: 'The total number of invocations of the test runner being run.',
       hide: true);
   parser.addOption("shard-index",
       help: 'The index of this test runner invocation (of --total-shards).',
       hide: true);
 
+  // If we're running test/dir/my_test.dart, we'll look for
+  // test/dir/my_test.dart.browser_test.dart.js in the precompiled directory.
+  parser.addOption("precompiled",
+      help: 'The path to a mirror of the package directory containing '
+          'precompiled JS.',
+      hide: true);
+
   return parser;
 })();
 
 /// The usage string for the command-line arguments.
 String get usage => _parser.usage;
 
 /// Parses the configuration from [args].
 ///
 /// Throws a [FormatException] if [args] are invalid.
 Configuration parse(List<String> args) => new _Parser(args).parse();
@@ skipping 48 matching lines @@
     return new Configuration(
         help: _ifParsed('help'),
         version: _ifParsed('version'),
         verboseTrace: _ifParsed('verbose-trace'),
         jsTrace: _ifParsed('js-trace'),
         pauseAfterLoad: _ifParsed('pause-after-load'),
         color: _ifParsed('color'),
         packageRoot: _ifParsed('package-root'),
         dart2jsPath: _ifParsed('dart2js-path'),
         dart2jsArgs: _ifParsed('dart2js-args') as List<String>,
+        precompiledPath: _ifParsed('precompiled'),
         reporter: _ifParsed('reporter'),
         pubServePort: _parseOption('pub-serve', int.parse),
         concurrency: _parseOption('concurrency', int.parse),
         shardIndex: shardIndex,
         totalShards: totalShards,
         timeout: _parseOption('timeout', (value) => new Timeout.parse(value)),
         patterns: patterns,
         platforms: (_ifParsed('platform') as List<String>)
             ?.map(TestPlatform.find),
         chosenPresets: _ifParsed('preset') as List<String>,
@@ skipping 24 matching lines @@
   /// information.
   /*=T*/ _wrapFormatException/*<T>*/(String name, /*=T*/ parse()) {
     try {
       return parse();
     } on FormatException catch (error) {
       throw new FormatException('Couldn\'t parse --$name "${_options[name]}": '
           '${error.message}');
     }
   }
 }