Added 'hand-tracking' in VRButton. Need to change to options though

examples/jsm/webxr/VRButton.js

@@ -71,7 +71,7 @@ var VRButton = {
 					// ('local' is always available for immersive sessions and doesn't need to
 					// be requested separately.)
 
-					var sessionInit = { optionalFeatures: [ 'local-floor', 'bounded-floor' ] };
+					var sessionInit = { optionalFeatures: [ 'local-floor', 'bounded-floor', 'hand-tracking' ] };
 					navigator.xr.requestSession( 'immersive-vr', sessionInit ).then( onSessionStarted );
 
 				} else {