WebXRManager: Clean up.

src/renderers/webxr/WebXRManager.js

@@ -137,15 +137,19 @@ function WebXRManager( renderer, gl ) {
 			session.addEventListener( 'squeezeend', onSessionEvent );
 			session.addEventListener( 'end', onSessionEnd );
 
+			var attributes = gl.getContextAttributes();
+
+			var layerInit = {
+				antialias: attributes.antialias,
+				alpha: attributes.alpha,
+				depth: attributes.depth,
+				stencil: attributes.stencil
+			};
+
 			// eslint-disable-next-line no-undef
-			session.updateRenderState( { baseLayer: new XRWebGLLayer( session, gl,
-				{
-					antialias: gl.getContextAttributes().antialias,
-					alpha: gl.getContextAttributes().alpha,
-					depth: gl.getContextAttributes().depth,
-					stencil: gl.getContextAttributes().stencil
-				}
-			) } );
+			var baseLayer = new XRWebGLLayer( session, gl, layerInit );
+
+			session.updateRenderState( { baseLayer: baseLayer } );
 
 			session.requestReferenceSpace( referenceSpaceType ).then( onRequestReferenceSpace );