I did a little bit of searching, and I think Chrome has something similar to the Tab Renamizer here. I'm still working on playing with it, but it seems pretty simplistic - click the icon and it lets you rename the tab. You have to do it manually for each tab, and each time you open a tab (if you had closed it before). It's really basic, and I'm not sure how the renamer for Firefox works so unfortunately I can't give any comparisons, but...it's functional?