PDFs are such a huge part of the internet, especially in academic and scientific circles. This (soon to be) stable feature inside the browser is amazing for finally providing a seamless experience when browsing PDFs online alongside webpages. There's no performance hit, no giant plugins to install, no Adobe Update Manager yelling at you every 15 minutes to update, restart your computer, and put the shortcut back on your desktop. The instant you click on the PDF it's available. A lot of people are reporting that they didn't even realize that they were looking at PDFs after the update. They just thought it was another webpage. That's how well integrated it is.
Great job Chrome Devs, you're really setting the browser ahead of the pack.