Open PDFs Automatically from Browser in Google Drive or Google PDF Viewer
Cloud Viewer add-on for Firefox opens PDF links without downloading the file. 


  View PDF, DOC, XLS and PPT files without downloading them to your device. Save downloading time and space on your device. Here's how it works: Just before a compatible file starts to download, you are prompted to open the file in the Google Docs Viewer instead. If you choose to open in the online viewer, a new tab is opened and the viewer is loaded.


It does give the print option also but I haven't verified it. Tested on Firefox 55.0.2, the latest on Play Store

On clicking a PDF link, you get a self explanatory dialog as below