WebXRManager: Fixed setCompatibleXRDevice() of null.

src/renderers/webvr/WebXRManager.js

@@ -74,8 +74,7 @@ function WebXRManager( renderer ) {
 	this.setDevice = function ( value ) {
 
 		if ( value !== undefined ) device = value;
-
-		gl.setCompatibleXRDevice( value );
+		if ( value instanceof XRDevice ) gl.setCompatibleXRDevice( value );
 
 	};
 

utils/build/externs.js

@@ -6,3 +6,4 @@ var performance;
 var createImageBitmap;
 var WebGL2RenderingContext;
 var XRWebGLLayer;
+var XRDevice;