WebVRManager: Fixed getFrameData warning.

src/renderers/webvr/WebVRManager.js

@@ -234,7 +234,7 @@ function WebVRManager( renderer ) {
 
 		var userHeight = frameOfReferenceType === 'stage' ? 1.6 : 0;
 
-		if ( device === null ) {
+		if ( isPresenting() === false ) {
 
 			camera.position.set( 0, userHeight, 0 );
 			return camera;
@@ -290,8 +290,6 @@ function WebVRManager( renderer ) {
 
 		poseObject.updateMatrixWorld();
 
-		if ( device.isPresenting === false ) return camera;
-
 		//
 
 		cameraL.near = camera.near;