Option to disable message widget

lib/src/dependency_graph.dart

 // Copyright (c) 2015, 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.
 
 /// Tracks the shape of the import/export graph and dependencies between files.
 library dev_compiler.src.dependency_graph;
 
 import 'dart:collection' show HashSet, HashMap;
 
 import 'package:analyzer/analyzer.dart' show parseDirectives;
@@ skipping 37 matching lines @@
   final CompilerOptions _options;
 
   SourceGraph(this._context, this._reporter, this._options) {
     var dir = _options.runtimeDir;
     if (dir == null) {
       _log.severe('Runtime dir could not be determined automatically, '
           'please specify the --runtime-dir flag on the command line.');
       return;
     }
     var prefix = path.absolute(dir);
-    var files =
-        _options.serverMode ? runtimeFilesForServerMode : defaultRuntimeFiles;
+    var files = _options.serverMode
+        ? runtimeFilesForServerMode(_options.widget)
+        : defaultRuntimeFiles;
     for (var file in files) {
       runtimeDeps.add(nodeFromUri(path.toUri(path.join(prefix, file))));
     }
   }
 
   /// Node associated with a resolved [uri].
   SourceNode nodeFromUri(Uri uri) {
     var uriString = Uri.encodeFull('$uri');
     return nodes.putIfAbsent(uri, () {
       var source = _context.sourceFactory.forUri(uriString);
@@ skipping 463 matching lines @@
   'dart._js_primitives',
   'dart.convert',
   'dart.mirrors',
   'dart._js_mirrors',
   'dart.js'
   // _foreign_helper is not included, as it only defines the JS builtin that
   // the compiler handles at compile time.
 ];
 
 /// Runtime files added to applications when running in server mode.
-final runtimeFilesForServerMode = new List<String>.from(defaultRuntimeFiles)
-  ..addAll(const ['messages_widget.js', 'messages.css']);
+List<String> runtimeFilesForServerMode([bool includeWidget = true]) =>
+    new List<String>.from(defaultRuntimeFiles)
+  ..addAll(includeWidget ? const ['messages_widget.js', 'messages.css'] : []);
 
 final _log = new Logger('dev_compiler.dependency_graph');