Google Chrome was developed keeping web apps in mind. Want a PDF Reader for Google Chrome? Why not add Google Docs integration with Google Chrome so that every PDF link can be viewed online before downloading it?
There are two extensions at the moment that can do this job – gPDF and Docs PDF/PowerPoint Viewer. The former scans for PDF links in any web page and sets them to open with Google Docs Viewer, while the latter is an extension developed by Google itself and can open PDF, PowerPoint, and other documents quickly.
You can give both extensions a shot and see which one suits you best. Since Docs PDF/PowerPoint Viewer cannot open .doc, .docx, .xls, .xlsx, etc formats, I am currently using gPDF and waiting for a better all-in-one extension to come out that can open various famous document formats online.