Google-chrome – opening files directly from Google Chrome

You can set the auto-open preferences for PDF files by clicking on the download status button in the downloads bar. When you have a downloaded PDF sitting there, click on the arrow and unselect "Always Open Files of This Type" in the pop-up menu.

You can also reset all the user preferences for auto-open by following the directions below from Chrome's help site at http://support.google.com/chrome/bin/answer.py?hl=en&answer=95759

If you want certain types of files to always open after they're done downloading, click the arrow next to the file button in the downloads bar and select Always open files of this type. To prevent potentially malicious files from automatically downloading to your computer, this option isn't available for executable filetypes, such as those with .exe, .dll, or .bat extensions (for Windows), and .dmg extensions (for Mac).

You can clear auto-opening settings through the Settings dialog. Here's how:

Click the wrench icon on the browser toolbar. Select Settings. Click the Under the Hood tab. In the "Downloads" section, click Clear auto-opening settings. This clears your settings for all file types. Click Close when you're done, if you're using Windows or Linux.

Smooth Gestures seems to provide this functionality by default.

There are some limitations though. One thing I noticed is, once you've gone all the way back in history to the new tab page, you can't move forward again, as the extension can't run on that page. Similarly, the extension also can't run in the Chrome Web Store for example.

I don't know how problematic that is in real-world use though.