CHM reader with Dropbox/Google Drive support in iPad? I would like to find some CHM reader which you can use to read CHM files which are located in Dropbox or Google Drive. 
I could not open books of those cloud services in CHMate premium, although there is a piece of advice about Dropbox how to do it: Offile storage > Open in but no CHMate button found. 

How can you read documents of cloud services in iPad?
This app looks to be your best bet. It has very limited reviews and very mixed feelings towards it.

It supports opening .chm files from Google Drive, but from one of the reviews, it has a bunch of ads that prevent viewing the files. You might need to pay the IAP (in-app purchase) for the "Pro Version." I'm not suggesting you do, as I haven't used it, but it is worth a try.