If I remember correctly, Pharrell ended up using Happy on NERD's album because Scott took too long to release it.
Remember, it was originally supposed to be a Velvet Revolver song.....
Edit: After a quick Google search, I guess it wasn't gonna be a VR song.
"Schedules being what they are, it's taken this long for the producer and the band to meet up. "He was insanely busy, we were busy ourselves, but it's finally coming together," McKagan said. Plus, in the time since they first met up, Pharrell's written a song called "Happy" that Weiland plans to use for his next solo record, since the singer said he felt the song spoke to recent experiences he'd gone through."