Bootstrap the rendering pipeline by scheduling the very first paint.
Requires that this render object is attached, is the root of the render tree, and has a composited layer.
See RenderView for an example of how this function is used.
Source
void scheduleInitialPaint(ContainerLayer rootLayer) {
assert(attached);
assert(parent is! RenderObject);
assert(!owner._debugDoingPaint);
assert(isRepaintBoundary);
assert(_layer == null);
_layer = rootLayer;
assert(_needsPaint);
owner._nodesNeedingPaint.add(this);
}