It could be a juvenile White-headed Munia like the two adults to the right, but these Munias do form mixed flocks and it looks a little dark on the head, although it is quite rufous-brown on the body and tail. I would expect juvenile Scaly-breasted to show prominent gape flanges, but I think there's a stage in their development when these disappear before they attain adult plumage, so I can't completely rule it out. At that stage they're rather uniform brown, though, and they tend to have silvery-blue bills. It doesn't look like Javan, which I think is fairly localised. One other possibility is juvenile Chestnut.