My dad switched to android from iphone and one of the things that really bugs him is that everytime he is looking at a pdf file it has to first download it to his downloads folder and then open it in his office suite on the oneplus two phone. He look at an average of around 20-30 pdfs on his phone that get sent to him daily with invoice and po numbers. He just opens them an gets the number and he is done with the file. So he ends up with a ton of pdf files in his downloads directory after just one week that he never needs again. What he is asking me to find is a way for it to just open in a new tab in firefox, so when he is done he just closes the tab. That is how it worked on safari on the iphone. On his desktop he has adobe reader installed and it does just like the iphone does, it opens a new tab and displays the pdf with an option at the top to save it if you want. Please see screenshot for example of pdf open in tab.

Thanks, Howard