Please see http://test-results.appspot.com/dashboards/flakiness_dashboard.html#showExpectations=true&useWebKitCanary=true&tests=printing%2Fsimultaneous-position-float-change.html for reference.
I'm temporarily updating the test_expectations to account for this failure.
It appears that the Chromium LayoutTestController implementation does not support the setPrinting() method:
CONSOLE MESSAGE: line 17: Uncaught TypeError: Object [object Object] has no method 'setPrinting'
I am going to fix this.
Resolved with fix for 46152, which enabled setPrinting for chromium LayoutTests.