in any case, from that article, it seems to be the only mention of possible violence. the article only says that:
… During the protest, the group chanted messages like “Long live the intifada,” “Hey hey, ho ho, the occupation has got to go” and “Killers on campus.” The crowd marched from Wheeler Hall at 6:00 p.m., to Zellerbach, where they were met by UCPD.
By 6:30 p.m, protestors had crowded side entrances to the building.
Officers struggled with the group at a side door of Zellerbach, one of them pushing a protester. UCPD officers stationed in Haas Pavilion moved towards the main entrance at 6:40 p.m. …
though, here’s a statement from the other side of things:
…
The Hillel further noted that they are supportive of the University holding the “disruptors” accountable “for their actions and destruction of university property.” …
“Breaking windows, intimidating students, and inciting a mob are never acceptable and have no place in civil discourse,” the statement read. …
Note that, the way I read it, it’s a general statement of “don’t be violent”, and it doesn’t sound to have been particularly violent. I imagine if they did in fact break windows, we’d have seen lots and lots of photos of that (in OP’s article.)