Brave crashed on macOS 10.12.3 via.window.open()

[We5ter]

Test plan

1. visit https://api.lightrains.org/poc/7.html
2. click link
3. verify alert shows and that Brave did not crash

Original issue description

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

Yes

• Describe the issue you encountered:

Brave crashed when visits poc.html

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

macOS10.12.3

• Brave Version (revision SHA):

0.13.2

• Steps to reproduce:
  1.poc script is:

<script>
function g(){

x=window; 
x.open('http://brave.com', 'z'); 
x.open('javascript:alert(1);', 'z'); 
}
</script>
CLICK ME

or visit online poc:

https://api.lightrains.org/poc/7.html

• Actual result:

crashed

• Expected result:

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

• 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:

[We5ter]

POC script doesn't show as expected,Please view source at my online POC to see full script,Thanks.

[bbondy]

cc @bridiver

[We5ter]

Another crash POC:https://api.lightrains.org/poc/7-2.html

[bridiver]

only the first one crashes for me on 2.56.3

[bridiver]

I think the other crash will likely be fixed by @bsclifton's changes. @bsclifton can you verify?

[bsclifton]

@bridiver verified; link is clicked, the alert is shown in a new about:blank tab 😄 (no crash)

Pulling into 0.13.5 as this will be fixed with #7107