Migrate to Chrome 37 IDL

tools/dom/templates/html/impl/impl_EventTarget.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 $LIBRARYNAME;
 
 /**
  * Base class that supports listening for and dispatching browser events.
  *
  * Normally events are accessed via the Stream getter:
@@ skipping 82 matching lines @@
 $(ANNOTATIONS)$(NATIVESPEC)$(CLASS_MODIFIERS)class $CLASSNAME$EXTENDS$IMPLEMENTS {
 
   // Custom element created callback.
   EventTarget._created();
 
   /**
    * This is an ease-of-use accessor for event streams which should only be
    * used when an explicit accessor is not available.
    */
   Events get on => new Events(this);
+
+  void addEventListener(String type, EventListener listener, [bool useCapture]) {
+    // TODO(leafp): This check is avoid a bug in our dispatch code when
+    // listener is null.  The browser treats this call as a no-op in this
+    // case, so it's fine to short-circuit it, but we should not have to.
+    if (listener != null) {
+      _addEventListener(type, listener, useCapture);
+    }
+  }
+
+  void removeEventListener(String type, EventListener listener, [bool useCapture]) {
+    // TODO(leafp): This check is avoid a bug in our dispatch code when
+    // listener is null.  The browser treats this call as a no-op in this
+    // case, so it's fine to short-circuit it, but we should not have to.
+    if (listener != null) {
+      _removeEventListener(type, listener, useCapture);
+    }
+  }
+
 $!MEMBERS
 }