Almost all modern browsers have this great feature, but with different names. In Google Chrome it is known as Incognito mode that you can enable from the option menu.
It requires only a click to switch your tab or window to private browsing mode or normal mode.
However, it should be noted that switching a tab or window to incognito mode will not remove the current records; it will remove only future records.
Incognito Switcher works only in Google Chrome 5.0 or higher versions. Download the add-on Incognito Switcher.