Okay, I downloaded an Chromebook emulator (CloudReady) to see if there were differences from my Chromebook. It looks like there were.
I don't know which version you've got but if it's more like the instructions from the mod, which is what the CloudReady emulator was like, then we need to modify the install a little from what I said in my post.
So, follow the mods install instructions and at step 6 it should show a popup named "Add a printer manually" with all the fields mentioned in the mods post. You'll need to put a printer name ("Canon MX922" or whatever you want to see when you go to print) and the IP address of your printer on your network. The IP address is important and must be set correctly for things to work. Check your printer if you don't know it and keep in mind that it can always change depending on how your network is configured so you may need to update this in the future. Leave Protocol to IPP and Queue to ipp/print. Click ADD.
At this point you'll get to the "Advanced printer configuration" screen. You can go back and follow the instructions I gave for this earlier since it's the same from here on. In short, leave the Manufacturer and Model blank and browse to get PPD file. ADD the printer and you should be finished. A new printer should appear with whatever name you gave it ("Canon MX922" or whatever).
The emulator seemed to support more features, like duplex printing, than my actual Chromebook so maybe things will work with these different instructions?
OMG! You are a genius. Works perfectly. How will I ever thank you? It has been so long. Bless you. I could not figure why I could print from the Canon Print App on my phone perfectly but not connect from my Asus CN62 Chromebox. I just ordered a new Asus Chromebox 4. I hope your PPD works from that. Again Thank you so much. You are the best!