Skill Swapping seems to also swap off whether or not you've been hit while charging Focus Punch.
http://replay.pokemonshowdown.com/vgc2015-271578383
Turn 1
Conkeldurr starts Focussing, then Ninjask hits it which should break the focus. Gengar then Skill Swaps Conkeldurr which seems to remove the effect of being hit, so Focus Punch still goes off.
The order things happen matters, as in this replay (http://replay.pokemonshowdown.com/vgc2015-271578125) the attack happens after Skill Swap and Conkeldurr loses focus.
http://replay.pokemonshowdown.com/vgc2015-271578383
Turn 1
Conkeldurr starts Focussing, then Ninjask hits it which should break the focus. Gengar then Skill Swaps Conkeldurr which seems to remove the effect of being hit, so Focus Punch still goes off.
The order things happen matters, as in this replay (http://replay.pokemonshowdown.com/vgc2015-271578125) the attack happens after Skill Swap and Conkeldurr loses focus.