Revert "Dartium JS Interop enabled."

tools/dom/src/dartium_KeyEvent.dart

 /**
  * A custom KeyboardEvent that attempts to eliminate cross-browser
  * inconsistencies, and also provide both keyCode and charCode information
  * for all key events (when such information can be determined).
  *
  * KeyEvent tries to provide a higher level, more polished keyboard event
  * information on top of the "raw" [KeyboardEvent].
  *
  * The mechanics of using KeyEvents is a little different from the underlying
  * [KeyboardEvent]. To use KeyEvents, you need to create a stream and then add
@@ skipping 11 matching lines @@
  *     stream.add(new KeyEvent('keypress', keyCode: 65, charCode: 97));
  *
  * This class is very much a work in progress, and we'd love to get information
  * on how we can make this class work with as many international keyboards as
  * possible. Bugs welcome!
  */
 part of html;
 
 @Experimental()
 class KeyEvent extends _WrappedEvent implements KeyboardEvent {
-  /** 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;
-
   /** The parent KeyboardEvent that this KeyEvent is wrapping and "fixing". */
   KeyboardEvent _parent;
 
   /** The "fixed" value of whether the alt key is being pressed. */
   bool _shadowAltKey;
 
   /** Caculated value of what the estimated charCode is for this event. */
   int _shadowCharCode;
 
   /** Caculated value of what the estimated keyCode is for this event. */
@@ skipping 103 matching lines @@
   int get _pageX => throw new UnsupportedError('Not applicable to KeyEvent');
   int get _pageY => throw new UnsupportedError('Not applicable to KeyEvent');
   @Experimental() // untriaged
   bool getModifierState(String keyArgument) => throw new UnimplementedError();
   @Experimental() // untriaged
   int get location => throw new UnimplementedError();
   @Experimental() // untriaged
   bool get repeat => throw new UnimplementedError();
   dynamic get _get_view => throw new UnimplementedError();
 }