There's a new Google app in the Play Store today—the Google PDF Viewer. You may be wondering why that exists seeing as Google Drive already opens PDFs. It's that same basic thing, but you don't need Drive. This app is intended mainly for Android for Work, but anyone can install it.
The Google PDF Viewer includes all the capabilities of the Drive-based viewer like printing, search, and copying text. This app is completely independent of the Drive app, so it's redundant to install it on most devices. It won't even appear in the app drawer as a dedicated app, so you don't gain any functionality without an Android for Work tie-in.
If you happen to need this app, you can grab it below. You probably don't, though.