Use the actual pipeline owner for this assert. (#7400)

packages/flutter/lib/src/widgets/gesture_detector.dart

@@ -382,11 +382,7 @@ class RawGestureDetectorState extends State<RawGestureDetector> {
   /// the gesture detector should be enabled.
   void replaceGestureRecognizers(Map<Type, GestureRecognizerFactory> gestures) {
     assert(() {
-      // TODO kgiesing This assert will trigger if the owner of the current
-      // tree is different from the owner assigned to the renderer instance.
-      // Once elements have a notion of owners this assertion can be written
-      // more clearly.
-      if (!RendererBinding.instance.pipelineOwner.debugDoingLayout) {
+      if (!context.findRenderObject().owner.debugDoingLayout) {
         throw new FlutterError(
           'Unexpected call to replaceGestureRecognizers() method of RawGestureDetectorState.\n'
           'The replaceGestureRecognizers() method can only be called during the layout phase. '