There is also a Google Chrome/Chromium extension also provided by the pdf.js team. (It's not in the webstore, though.)
I've used it since about half a year and I like it a lot. (Not having to download PDFs all the time and having PDFs in tabs alongside the sites I read.)
You can also separately download the proprietary PDF reader of Chrome and use it with Chromium. If you are using Arch Linux, it is available in the repositories.
I've used it since about half a year and I like it a lot. (Not having to download PDFs all the time and having PDFs in tabs alongside the sites I read.)