Adding supported checks for Element.matches.

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

 // 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.
 
 part of html;
 
 // TODO(jacobr): use _Lists.dart to remove some of the duplicated
 // functionality.
 class _ChildrenElementList implements List {
   // Raw Element.
@@ skipping 877 matching lines @@
       case 'afterend':
         this.parentNode.insertBefore(node, this.nextNode);
         break;
       default:
         throw new ArgumentError("Invalid position ${where}");
     }
   }
 
   /**
    * Checks if this element matches the CSS selectors.
+   *
+   * Use [supportsMatches] to check if this is supported on the current
+   * platform.
+   *
+   * See also:
+   *
+   * * [supportsMatches]
    */
+  @SupportedBrowser(SupportedBrowser.CHROME)
+  @SupportedBrowser(SupportedBrowser.FIREFOX)
+  @SupportedBrowser(SupportedBrowser.IE, '10')
+  @SupportedBrowser(SupportedBrowser.SAFARI)
   @Experimental
   bool matches(String selectors) {
     if (JS('bool', '!!#.matches', this)) {
       return JS('bool', '#.matches(#)', this, selectors);
     } else if (JS('bool', '!!#.webkitMatchesSelector', this)) {
       return JS('bool', '#.webkitMatchesSelector(#)', this, selectors);
     } else if (JS('bool', '!!#.mozMatchesSelector', this)) {
       return JS('bool', '#.mozMatchesSelector(#)', this, selectors);
     } else if (JS('bool', '!!#.msMatchesSelector', this)) {
       return JS('bool', '#.msMatchesSelector(#)', this, selectors);
     }
   }
+
+  /**
+   * Checks if the matches function is supported on the current platform.
+   *
+   * See also:
+   *
+   * * [matches]
+   */
+  static bool get supportsMatches {
+    var e = new DivElement();
+    return JS('bool', '!!(#.matches || #.webkitMatchesSelector || '
+      '#.mozMatchesSelector || #.msMatchesSelector)', e, e, e, e);
+  }
 $else
+  /**
+   * Checks if the matches function is supported on the current platform.
+   *
+   * See also:
+   *
+   * * [matches]
+   */
+  static bool get supportsMatches => true;
 $endif
 
 $!MEMBERS
 }
 
 final _START_TAG_REGEXP = new RegExp('<(\\w+)');
 class _ElementFactoryProvider {
   static const _CUSTOM_PARENT_TAG_MAP = const {
     'body' : 'html',
     'head' : 'html',
@@ skipping 122 matching lines @@
 $if DART2JS
   // Optimization to improve performance until the dart2js compiler inlines this
   // method.
   static dynamic createElement_tag(String tag) =>
       JS('Element', 'document.createElement(#)', tag);
 $else
   static Element createElement_tag(String tag) =>
       document.$dom_createElement(tag);
 $endif
 }