download leaves about:blank page loading

[bridiver]

Test Plan

Go to http://www.dynonavionics.com/af-5000-software-updates.php
Click on Download under "AF-5000 System Software Package"
Ensure the about:blank page opened is closed after download starts

• Did you search for similar issues before submitting this one?
  Yes

• Describe the issue you encountered:
  Some downloads create an about:blank page that stays open when the download starts

• Platform (Win7, 8, 10? macOS? Linux distro?):
  macOS

• Brave Version (revision SHA):
  0.16.9

• Steps to reproduce:

  1. Go to http://www.dynonavionics.com/af-5000-software-updates.php
  2. Click on Download under "AF-5000 System Software Package"

• Actual result:
  File downloads, but leaves an open about:blank page

• Expected result:
  about:blank page should close when download starts (this is what happens on chrome)

• Will the steps above reproduce in a fresh profile? If not what other info can be added?
  Yes

• Is this an issue in the currently released version?
  Yes

• Can this issue be consistently reproduced?
  Yes

• Extra QA steps:
  1.
  2.
  3.

• Screenshot if needed:

• Any related issues: