A bug was introduced in r27717 that broke the "icon database thread is running" check. This check is currently always returning false. This means we don't wait until the thread has shut down during icon database closes, and also allows the icon database to be disposed out from under the icon database thread.
Created attachment 29182 [details] Set m_syncThreadRunning
Comment on attachment 29182 [details] Set m_syncThreadRunning r=me
Fixed in r42163.