Consolidating platform code into dart:html_common

tools/dom/templates/html/impl/impl_Event.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.
 
 // WARNING: Do not edit - generated code.
 
 part of $LIBRARYNAME;
 
 $(ANNOTATIONS)class $CLASSNAME$EXTENDS$IMPLEMENTS$NATIVESPEC {
   // In JS, canBubble and cancelable are technically required parameters to
@@ skipping 16 matching lines @@
    *
    *     var e = new Event.type('MouseEvent', 'mousedown', true, true);
    */
   factory Event.eventType(String type, String name, {bool canBubble: true,
       bool cancelable: true}) {
     final Event e = document.$dom_createEvent(type);
     e.$dom_initEvent(name, canBubble, cancelable);
     return e;
   }
 $!MEMBERS
-
-  /**
-   * Checks to see if the event class is supported by the current platform.
-   */
-  static bool _isTypeSupported(String eventType) {
-    // Browsers throw for unsupported event names.
-    try {
-      var e = document.$dom_createEvent(eventType);
-      return e is Event;
-    } catch (_) { }
-    return false;
-  }
 }