Revert "Dartium JS Interop enabled."

tools/dom/src/dartium_WrappedEvent.dart

Index: tools/dom/src/dartium_WrappedEvent.dart
diff --git a/tools/dom/src/dartium_WrappedEvent.dart b/tools/dom/src/dartium_WrappedEvent.dart
index 9fa56fd9ddecdc8a423e3318172d2f39415d22b4..2f7b8b8345a0baf709ddf769a80706da6437ecda 100644
--- a/tools/dom/src/dartium_WrappedEvent.dart
+++ b/tools/dom/src/dartium_WrappedEvent.dart
@@ -8,13 +8,6 @@ part of dart.html;
  * Helper class to implement custom events which wrap DOM events.
  */
 class _WrappedEvent implements Event {
-  /** Needed because KeyboardEvent is implements.
-   *  TODO(terry): Consider making blink_jsObject private (add underscore) for
-   *               all blink_jsObject.  Then needed private wrap/unwrap_jso
-   *               functions that delegate to a public wrap/unwrap_jso.
-   */
-  js.JsObject blink_jsObject;
-
   final Event wrapped;
 
   /** The CSS selector involved with event delegation. */