That is strange - I wouldn't expect any new highrises would be allowed on Robson itself. I could see them taking down a Pacific Palisades tower and building a new one in its place at 1277 Robson (even if not on Robson itself). But 1177 Robson is a large enough site (London Drugs and earls) to allow for a tower.
EDIT: It probably is the Hilton site at 177 Robson, although hotel units on 2nd to 4th floors? 2nd to 14th maybe?
Relative Form is the architect for the Hilton Hotel project:
http://aibc.memberpro.net/main/body....&table_id=1067