Second round of cleanups for new optional parameter semantics.

utils/css/world.dart

 // Copyright (c) 2012, 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.
 
 /** The one true [World]. */
 World world;
 
 typedef void MessageHandler(String prefix, String message, SourceSpan span);
 typedef void PrintHandler(String message);
 
@@ skipping 117 matching lines @@
   void fatal(String message,
       [SourceSpan span, SourceSpan span1, SourceSpan span2]) {
     errors++;
     seenFatal = true;
     _message(_RED_COLOR, 'fatal: ', message,
         span, span1, span2, options.throwOnFatal || options.throwOnErrors);
   }
 
   /** [message] at [location] is about a bug in the compiler. */
   void internalError(String message,
-      [SourceSpan span, SourceSpan span1, SourceSpan span2]) {
+      {SourceSpan span, SourceSpan span1, SourceSpan span2}) {
     _message(_NO_COLOR,
         'We are sorry, but...', message, span, span1, span2, true);
   }
 
   /**
    * [message] at [location] will tell the user about what the compiler
    * is doing.
    */
   void info(String message,
       [SourceSpan span, SourceSpan span1, SourceSpan span2]) {
@@ skipping 12 matching lines @@
     info('$name in ${sw.elapsedInMs()}msec');
     return result;
   }
 }
 
 // Color constants used for generating messages.
 String _GREEN_COLOR = '\u001b[32m';
 String _RED_COLOR = '\u001b[31m';
 String _MAGENTA_COLOR = '\u001b[35m';
 String _NO_COLOR = '\u001b[0m';