Update web_command code so that it continues to use the legacy module loader. Drive by removal of m…

pkg/dev_compiler/web/main.dart

 #!/usr/bin/env 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.
 
-/// Command line entry point for Dart Development Compiler (dartdevc).
-///
-/// Supported commands are
-///   * compile: builds a collection of dart libraries into a single JS module
-///
-/// Additionally, these commands are being considered
-///   * link:  combines several JS modules into a single JS file
-///   * build: compiles & links a set of code, automatically determining
-///            appropriate groupings of libraries to combine into JS modules
-///   * watch: watch a directory and recompile build units automatically
-///   * serve: uses `watch` to recompile and exposes a simple static file server
-///            for local development
-///
-/// These commands are combined so we have less names to expose on the PATH,
-/// and for development simplicity while the precise UI has not been determined.
-///
-/// A more typical structure for web tools is simply to have the compiler with
-/// "watch" as an option. The challenge for us is:
-///
-/// * Dart used to assume whole-program compiles, so we don't have a
-///   user-declared unit of building, and neither "libraries" or "packages" will
-///   work,
-/// * We do not assume a `node` JS installation, so we cannot easily reuse
-///   existing tools for the "link" step, or assume users have a local
-///   file server,
-/// * We didn't have a file watcher API at first,
-/// * We had no conventions about where compiled output should go (or even
-///   that we would be compiling at all, vs running on an in-browser Dart VM),
-/// * We wanted a good first impression with our simple examples, so we used
-///   local file servers, and users have an expectation of it now, even though
-///   it doesn't scale to typical apps that need their own real servers.
-
 @JS()
 library dev_compiler.web.main;
 
 import 'dart:async';
 
 import 'package:args/command_runner.dart';
 import 'package:js/js.dart';
 
 import 'web_command.dart';
 
-@JS()
+@JS(r'$setUpDartDevCompilerInBrowser')
 external set setUpCompilerInBrowser(Function function);
 
 Future main() async {
   var args = ['compile'];
   _runCommand(args);
 }
 
 /// Runs a single compile command, and returns an exit code.
 Future<int> _runCommand(List<String> args,
     {MessageHandler messageHandler}) async {
@@ skipping 42 matching lines @@
     messageHandler("");
     messageHandler("    dartdevc arguments: " + args.join(' '));
     messageHandler("");
     messageHandler("```");
     messageHandler(error);
     messageHandler(stackTrace);
     messageHandler("```");
     return 70;
   }
 }