Err... hasn't it just been renamed Auto Tone from Auto?
Clicking on Auto Tone disables the Exposure>White parameters in PS26, as does clicking on Auto in PS21, so it looks like it's having the same effect.
I can see that in 26 by opening a clip in the Corrections editor from the
Library and in the Edior under. Editor/Colour/Basic and
Editor/Effect/Colour/Image correction CPU.