Some of the files used in restoring applications are located at
~/Library/Saved Application State. These files are updated while an application is running, and if it crashes they are used by the system to restore it (if the application crashes during the restore process, OS X offers to discard the saved state when relaunching a second time).
But some applications such as Chrome store more information elsewhere. Chrome stores your open tabs and other data in
~/Library/Application Support/Google/Chrome/Default. There I see files such as
Last Session and
Last Tabs. (For comparison, Safari uses