Tripping Strike -- Still critical damage or not?

[Celeborne]

As the title...

D20PFSRD wrote:

Tripping Strike:
Prerequisites: Int 13, Combat Expertise, Improved Trip, base attack bonus +9.

Benefit: Whenever you score a critical hit with a melee attack, you can trip your opponent, in addition to the normal damage dealt by the attack. If your confirmation roll exceeds your opponent’s CMD, you may knock your opponent prone as if from the trip combat maneuver. This does not provoke an attack of opportunity. If you are tripped during your own trip attempt, you can drop your weapon to avoid being tripped.

In this case, what does normal damage constitute? Is it still a critical in terms of damage multiplier if the confirmation roll hits, or does one forego the critical damage in order to trip their target?

[Talonhawke]

Yes to my knowledge nothing about applying a critical feat in and of itself reduces the damage.

[Java Man]

"Normal damage" for a critical hit is damage with the multiplier applied. As I see it.