Thought I'd put this up, because I was unable to find a fix for this through Google or any other means, though I'm sure it has happened to someone before. Yesterday my Chromium browser started acting strange to say the least. It was getting very, very slow, as well as giving a large amount of "Tab not responding" windows. Eventually, the tab bar and main frame were both unresponsive, taking maybe 30 minutes to respond to clicks(including minimize, maximize and close buttons) and even when responding, they would not behave properly.(closing a tab would not move all tabs back to the left, and the closed tab would become about 10 pixels wide instead of completely disappearing) The wierder thing, though, is that the toolbar(bookmarks, address bar, settings) all still worked, so long as it didn't need to open a tab.
This was very frustrating, as restarts of either the browser or the system did nothing. I tried renaming my "~/.config/chromium" directory to see if that would fix it, and it did, but of course I want all my settings. I started going through all the contents of the config directory until I found the offending files.(not sure which one specifically) The corrupt file causing the problem was in "~/.config/chromium/Default/Local Storage", and once I deleted the directory, the problem was gone.
Hopefully this helps someone, I'm sure there are others who have run into similar problems and not wanted to completely reset all of their history, bookmarks, etc. I'm still not 100% what caused the problem, though I notice now that there are only 3 files in the Local Storage, and there were 10+ when I deleted it. I also had the browser open for days with 10+ tabs, I may have pushed the browser a bit hard. Either way, as I said, hopefully anyone with this problem finds this post :)