Fix a type warning for SVGElement.tag.

client/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 _TextFactoryProvider {
 
   factory Text(String data) => _document._createTextNode(data);
 }
 
 class _EventFactoryProvider {
@@ skipping 115 matching lines @@
     e.innerHTML = svg;
 
     // Copy list first since we don't want liveness during iteration.
     final List nodes = new List.from(e.nodes);
     fragment.nodes.addAll(nodes);
     return fragment;
   }
 }
 
 class _SVGElementFactoryProvider {
-  factory SVGElement.tag(String tag) =>
-    _document._createElementNS("http://www.w3.org/2000/svg", tag);
+  factory SVGElement.tag(String tag) {
+    final Element temp =
+      _document._createElementNS("http://www.w3.org/2000/svg", tag);
+    return temp;
+  }
 
   factory SVGElement.svg(String svg) {
     Element parentTag;
     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('SVG had ${parentTag.elements.length} ' +
         'top-level elements but 1 expected');
   }
 }
 
 class _SVGSVGElementFactoryProvider {
   factory SVGSVGElement() {
     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;
   }
 }