The system has been in place in Canada for decades for HRSDC to issue a  Labour Market Impact Assessment (LMIA) formerly a Labour Market Opinion (LMO) ) to a specific employer for a specific job for a named TFW unless there is a specific exemption (such as a Mexican or American  professional under NAFTA).  The LMIA certifies that the particular job meets the Canadian standards for wages, working conditions, etc and that there are no Canadian Citizens or Permanent Residents reasonably available to fill the job.
http://www.cic.gc.ca/english/resources/tools/temp/work/opinion/

In certain sectors such as high tech where there is a clear shortage of workers, sector LMIAs  for specific occupations have been issued in the past.

It was a myth perpetrated by some that there was no clearance procedure.  That was an "alternate fact".