When a page is loading under Chrome on Linux, a spinner is show in the tab where the favicon is normally displayed. It isn't a "progress bar" but it is an indication that the page has not fully loaded yet.
Sidenote: The Amazon App Store app on Android does something similar. I've seen other apps do this as well but I can't think of them at the moment. Is this a design pattern we will see more of like the Ajax spinners of the Web 2.0 craze?