TORONTO — The move by the federal government to force Chinese companies to sell their investments in three junior mining companies is being called a meaningful and necessary escalation of Canada's defensive posturing on strategic assets. TORONTO — The move by the federal government to force Chinese companies to sell their investments in three junior mining companies is being called a meaningful and necessary escalation of Canada's defensive posturing on strategic assets. Aaron Shull, managing director at the Centre for International Governance Innovation, says the actions show the government is now on their front foot as it recognizes the need…