How can I change the default Google Drive PDF viewer on Android?
I had the same problem using Firefox on Android - totally maddening - but fixed it.

After installing Google Drive all my links to pdfs would open with Google Drive PDF Viewer.

I fixed it by, in Firefox, going to about:config in the location bar, then finding "browser.download.preferred.application/pdf" and doing a Reset there.

The next time I clicked on a link to a pdf I got the choice to Download, or use Google Drive PDF Viewer.

Shouldn't it be there in Chrome, under the hood somewhere ?

Btw, that "browser.download.preferred.application/pdf" in Firefox only seems to show up after a choice has been made, in this case, forced by the install of Google Drive. Seems redolent of the old browsers wars.