Not aware there is a riot in 2009. Wow, that is quite recent.
Yes, these violent protests started with the one in Seattle.
There are various groups there in Toronto protesting, some of these groups are the anti-poverty group, women rights, Socialist Worker Organization, Schwarzer Block, Anti-Capitalist Convergence, Black Bloc etc. The five relevant groups involved in the Toronto protests in the context of migration are the Stormfront, Nisga Nation, Aryan Guard, Creativity Movement and the Neo Nazis. All five groups opposes immigration and some of the groups are racist and hate groups. These protesters are there to protest to limit the number of immigrants to Canada or ban immigration to Canada from non-European countries.