Fixing Element.matches to be cross-platform and follow latest spec.

sdk/lib/html/dart2js/html_dart2js.dart

Index: sdk/lib/html/dart2js/html_dart2js.dart
diff --git a/sdk/lib/html/dart2js/html_dart2js.dart b/sdk/lib/html/dart2js/html_dart2js.dart
index 848997d6c88f22379c2ac5d9a3375dc933c78292..c4a0b8f647aba385ff1326da1c8f0951ce0b81bb 100644
--- a/sdk/lib/html/dart2js/html_dart2js.dart
+++ b/sdk/lib/html/dart2js/html_dart2js.dart
@@ -6183,7 +6183,6 @@ class DocumentFragment extends Node native "*DocumentFragment" {
       _emptyStyleFuture();
   Future<CssStyleDeclaration> getComputedStyle(String pseudoElement) =>
       _emptyStyleFuture();
-  bool matchesSelector(String selectors) => false;
 
   // Imperative Element methods are made into no-ops, as they are on parentless
   // elements.
@@ -7697,6 +7696,22 @@ abstract class Element extends Node implements ElementTraversal native "*Element
     }
   }
 
+  /**
+   * Checks if this element matches the CSS selectors.
+   */
+  @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);
+    }
+  }
+
 
   /// @domName EventTarget.addEventListener, EventTarget.removeEventListener, EventTarget.dispatchEvent; @docsEditable true
   ElementEvents get on =>
@@ -7908,10 +7923,6 @@ abstract class Element extends Node implements ElementTraversal native "*Element
   /// @domName Element.webkitCreateShadowRoot; @docsEditable true
   ShadowRoot webkitCreateShadowRoot() native;
 
-  /// @domName Element.webkitMatchesSelector; @docsEditable true
-  @JSName('webkitMatchesSelector')
-  bool matchesSelector(String selectors) native;
-
   /// @domName Element.webkitRequestFullScreen; @docsEditable true
   void webkitRequestFullScreen(int flags) native;