Infinity Edge

applies for its full effect on ashe. her passive works in a way where she deals on average the same damage to champions over all of her auto attacks, as if she would crit normally. crit damage bonus is worked into the formula. with a 10% damage bonus so her passive actually does something.

i.e. also applies to yasuo, but not for full 250% total.

take a look on lolwiki.

edit.: actually it should be 225% crit damage for yasuo with an infinity edge. 250% from the item, and then his passive reduces that 2.5 multiplyer by 10% (minus 25% crit damage).