Merge pull request #16462 from Mugen87/dev7

WebVR: Make XR test more robust.

examples/js/vr/WebVR.js

@@ -131,7 +131,7 @@ var WEBVR = {
 
 		}
 
-		if ( 'xr' in navigator ) {
+		if ( 'xr' in navigator && 'requestDevice' in navigator.xr ) {
 
 			var button = document.createElement( 'button' );
 			button.style.display = 'none';

src/renderers/WebGLRenderer.js

@@ -308,7 +308,7 @@ function WebGLRenderer( parameters ) {
 
 	// vr
 
-	var vr = ( typeof navigator !== 'undefined' && 'xr' in navigator ) ? new WebXRManager( _this ) : new WebVRManager( _this );
+	var vr = ( typeof navigator !== 'undefined' && 'xr' in navigator && 'requestDevice' in navigator.xr ) ? new WebXRManager( _this ) : new WebVRManager( _this );
 
 	this.vr = vr;