Repro for crbug.com/1295750

This illustrates the problem that window.onerror handlers and 'error' events aren't fired by Console errors.

Steps

1. Open DevTools
2. Click this button
3. Observe that both onerrorHandler and errorHandler were run
4. Paste throw new Error('Error from console') into the Console and run it
5. Observe that neither onerrorHandler nor errorHandler were run