Change IllegalArgumentException to ArgumentError.

lib/html/src/shared_FactoryProviders.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.
 
 class _EventFactoryProvider {
   static Event createEvent(String type, [bool canBubble = true,
       bool cancelable = true]) {
     final _EventImpl e = _document.$dom_createEvent("Event");
     e.$dom_initEvent(type, canBubble, cancelable);
     return e;
@@ skipping 73 matching lines @@
     final match = _START_TAG_REGEXP.firstMatch(svg);
     if (match != null && match.group(1).toLowerCase() == 'svg') {
       parentTag = new Element.tag('div');
     } else {
       parentTag = new SVGSVGElement();
     }
 
     parentTag.innerHTML = svg;
     if (parentTag.elements.length == 1) return parentTag.nodes.removeLast();
 
-    throw new IllegalArgumentException(
+    throw new ArgumentError(
         'SVG had ${parentTag.elements.length} '
         'top-level elements but 1 expected');
   }
 }
 
 class _SVGSVGElementFactoryProvider {
   static SVGSVGElement createSVGSVGElement() {
     final el = new SVGElement.tag("svg");
     // The SVG spec requires the version attribute to match the spec version
     el.attributes['version'] = "1.1";
     return el;
   }
 }