Santa Anita is a horse track, not a cardroom. In the past they apparently had an annual charity-night poker game and the chip might have been from that. Sometimes the track simply gives out a chip to the first 100 or so persons to enter, along with maybe a T-shirt; a promo item.

Here's more info on the charity games --

http://bestevents.us/arcadia-third-annual-day-at-the-races-at-santa-anita-park/4254