YVR-DFW-MIA-GYE-MIA-DFW-YVR.

MIA-GYE-MIA will have meal service. DFW-MIA and back no chance. YVR-DFW on the schedule currently says a meal at mealtimes or a snack. Whether that reflects the latest meal changes i.e. no bistro bags I don't know. According to AA, now, only flights over four hours and those from DFW-JFK/EWR/LGA and BOS receive meal service.

Here's the tricky part though. YVR-DFW is, gate-to-gate, scheduled at 4hr7m. AA doesn't count gate-to-gate time though. They rely on flying time to determine whether a flight warrants a meal or not. You can't get the flying time from the website. AA has padded it's schedule for many years now and it's usually on the order of 20 mins or so.

The only way to know for sure is to call. Since they are changing things up in Y food-wise, you'd be well to call a day or two before departure to make sure you have the latest info.