second window is opened when launching 0.21.11 for the second time

[LaurenWags]

Description

If you open 0.21.11 with a clean profile, you get one window, with one tab as expected. If you close Brave-Beta and open again, you now have two windows. This second window has the welcome page (about:welcome).

Test plan / Steps to Reproduce

1. Launch 0.21.11 with a clean profile.
2. See one window with one tab.
3. Close Brave-Beta.
4. Open Brave-Beta again.

Actual result:
Two windows are displayed.

Expected result:
Only one window.

Reproduces how often:
Easily on MacOS. @kjozwiak reported he has seen it on Win 10 x64 but not consistently.

Brave Version

about:brave info:
0.21.11

Reproducible on current live release:
no

Additional Information

[petemill]

It's weird that the welcome tab does not show on the first load, but does on the second. I have a feeling the welcome tab is being added to the buffer window. Which is then being saved to state because it does not have 0 tabs.

[petemill]

Hopefully fixed with #13244

[srirambv]

Verified on Windows x64

• 0.22.6 e6ff4ea
• libchromiumcontent: 65.0.3325.162
• muon: 5.1.0

Verified on macOS 10.12.6 x64 using the following build:

• 0.22.6 e6ff4ea
• libchromiumcontent: 65.0.3325.162
• muon: 5.1.0

Verified on Ubuntu 10.10 x64

• 0.22.6 e6ff4ea
• libchromiumcontent: 65.0.3325.162
• muon: 5.1.0