Jacob is under bankruptcy protection, and are "reorganizing". During Jacob's corporate/financial reorganization, they don't plan on closing any stores.
The new stores in Sherway would likely come from the closing of other stores, possibly including the temporary stores like Laura Coats and the calendar/games store. There are also one or two "vacant" stores within the mall.
Jacob may have already been in the process of consolidating their Sherway stores. Besides, closing one out of two stores in a mall probably wouldn't count as "closing" a store since they'd be combining two stores at Sherway.
But who knows. Maybe they don't plan on closing a Sherway store.
EDIT
I was looking a bit more into 20 VIC. They do own some smaller regional malls, of which a few have H&Ms in them:
TD Square/Calgary Eaton Centre (561,084 sq ft) last renovated 2010
Lougheed Town Centre (657,146 sq ft) last renovated early 2000s
Pickering Town Centre (894,640 sq ft) last renovated 2009
Lansdowne Place (436,267 sq ft) last renovated 2009
Pen Centre (1,036,696 sq ft) last renovated 2004/2005
Erin Mills (799,000 sq ft) last renovated, um, never
So I sure hope 20 VIC invests in Erin Mills by renovating it, since Cadillac Fairview was too lazy to bother renovating (I don't count the replacement of the movie theatre and mini golf as "renovation" since the look of the mall didn't really change at all. It was built in 1990 so it's due for a renovation. Unless some of the Eaton Centre purists think Erin Mills should remain true to it's late 80s sensibilities.