Google has launched a standalone PDF Viewer on Android which has had people ask questions when we already have Google Drive.
This is no doubt aimed for people that are on the go with their Android devices.PDF Viewer is primarily meant for use in the context of the Android for Work Program (http://android.com/work).
PDF Viewing is now available directly in Google Drive. For environments where this cannot be deployed, Google PDF Viewer offers the same capabilities in a standalone app. View, print, search and copy text from pdf documents while you’re on the go.