Cleanup of various DOM dart2js and dart_analyzer warnings

tools/dom/templates/html/impl/impl_SVGElement.darttemplate

 // Copyright (c) 2011, 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.
 
 part of $LIBRARYNAME;
 
 class _AttributeClassSet extends CssClassSetImpl {
   final Element _element;
 
   _AttributeClassSet(this._element);
@@ skipping 26 matching lines @@
       _$(CLASSNAME)FactoryProvider.create$(CLASSNAME)_svg(svg);
 
   _AttributeClassSet _cssClassSet;
   CssClassSet get classes {
     if (_cssClassSet == null) {
       _cssClassSet = new _AttributeClassSet(this);
     }
     return _cssClassSet;
   }
 
-  List<Element> get children => new FilteredElementList(this);
+  List<Element> get children => new FilteredElementList<Element>(this);
 
   void set children(List<Element> value) {
     final children = this.children;
     children.clear();
     children.addAll(value);
   }
 
   String get outerHtml {
     final container = new Element.tag("div");
     final SvgElement cloned = this.clone(true);
@@ skipping 46 matching lines @@
    * Checks to see if the SVG element type is supported by the current platform.
    *
    * The tag should be a valid SVG element tag name.
    */
   static bool isTagSupported(String tag) {
     var e = new $CLASSNAME.tag(tag);
     return e is $CLASSNAME && !(e is UnknownElement);
   }
 $!MEMBERS
 }