When I use my Chromebook, it is not possible to view a PDF file. Unless I use a app from the Chrome Web Store...or, as I learned "by accident", have the Evernote Web Clipper installed:
"If you've opened a PDF document in your browser, you can save the entire PDF document as an attachment to a new note in your Evernote account."
Though I had the document opened in the browser, I did not choose to enable the "Chrome PDF Viewer". When offline, I might need to...but for now, when online, I'm satisfied with the features provided by Evernote:
"When you view a PDF in your browser, simply click the Web Clipper icon. You can assign a destination notebook, tags and some additional notes. That’s all. The PDF will be placed into your Evernote account and synched so that you can view it from any computer or device where Evernote is installed."
AND...via http://Evernote.com (in the web browser while online), I can read the PDF document!