Yeah except he literally didn't "perform any act common to the game" so that clause of the rulebook is moot. I mean in the very page of the NFL rulebook you cited you deliberately ignored the very next clause.
2: If a player, who satisfied (a) and (b), but has not satisfied (c), contacts the ground and loses control of the ball, it is an incomplete pass if the ball hits the ground before he regains control, or if he regains control out of bounds"
It comes down to what you think you saw, but it's been the ruling forever that if the ground knocks the ball loose in your hands, that's an incomplete pass.
I mean quite frankly you could even make the case that as the ball is knocked loose by contact with the ground and Henry slides onto the white paint before it stops moving, he "regained control out of bounds."