Detect vpn service is not launched in runtime and fallback to DoH

[spylogsster]

Test plan

See brave/brave-core#17013

Description

If brave vpn helper service was not launched by some reasons we have to detect it in runtime and fallback to DoH to protect users from DNS leaks

[LaurenWags]

@spylogsster @bsclifton is this Windows only?

[spylogsster]

@spylogsster @bsclifton is this Windows only?

yes, added label

[stephendonner]

Verification PASSED using

Brave	1.50.99 Chromium: 111.0.5563.64 (Official Build) beta (64-bit)
Revision	c710e93d5b63b7095afe8c2c17df34408078439d-refs/branch-heads/5563@{#995}
OS	Windows 11 Version 21H2 (Build 22000.1696)

Steps:

1. installed 1.50.99
2. launched Brave
3. restarted (to pick up Griffin changes and enable VPN button)
4. loaded account.brave.com
5. logged in using my stephen-prod@mailinator.com account
6. clicked on Refresh Brave VPN button to obtain new credentials
7. clicked on the VPN button in the browser toolbar
8. toggled from Disconnected to Connected
9. confirmed I saw the modal dialog about Windows' Smart Multi-Homed Name Resolution and our Brave-helper-service workaround
10. pressed ctrl + alt + del to open Task Manager
11. context-clicked on the Name column and checked Command line
12. looked at the list of Apps and Background processes
13. confirmed I saw no Brave VPN Helper service (brave_vpn_helper.exe in the background-processes list
14. loaded https://www.browserleaks.com/dns
15. compared results to those using the helper service
16. opened brave://settings/security
17. compared fall-back settings to those using the helper service

Confirmed the following:

• While connected -- and without the helper service active -- we fall-back to DNS-over-HTTPS support, via Cloudflare
• The above Use secure DNS settings is locked by BraveVPN while it is connected
• We don't leak the user's ISP DNS servers
• While disconnected, defaults for Use secure DNS / With your current service provider are used

Brave VPN, Connected

Helper-service modal dialog	brave://settings/privacy

Brave VPN, Disconnected

browserleaks.com/dns	brave://settings/privacy

Windows 11	Windows 10

Windows 11	Windows 10

[stephendonner]

Leaving QA/Pass-Win64 as this should also be tested on Windows 10.

[GeetaSarvadnya]

Verification PASSED on

Brave | 1.50.101 Chromium: 111.0.5563.116 (Official Build) beta (64-bit)
-- | --
Revision | ade86b9472831e26d87fd569e04b404be01e1e2b-refs/branch-heads/5563@{#1209}
OS | Windows 10 Version 21H2 (Build 19044.2728)

• confirmed I saw the modal dialog about Windows' Smart Multi-Homed Name Resolution and our Brave-helper-service
• open Task Manager and ensured Brave VPN Helper service is running Details tab in task manager VPN is connected
• ensured BraveberaVpnService is listed under the Service tab in task manager
• ensured Brave VPN Helper is running under background apps when VPN is connected

Connected to BraveVPN	Task Manager	Details	Services panel

Brave VPN, Connected

Confirmed the following:

• While connected -- and with the helper service active -- we fall-back to DNS-over-HTTPS support, via Cloudflare
• The Use secure DNS settings is locked by BraveVPN while it is connected, logged Use secure DNS is locked when brave_vpn_helper service is running #29338
• We don't leak the user's ISP DNS servers when VPN is connected

Helper-service modal dialog	brave://settings/privacy

Brave VPN, Disconnected

Confirmed the following:

• While disconnected, defaults for Use secure DNS / With your current service provider are used

browserleaks.com/dns	brave://settings/privacy

[GeetaSarvadnya]

Verified the issue on Windows 11 x64 - 1.50.106, I saw some discrepancies which are listed below:

1. When VPN is connected I have observed the below:
   • confirmed I saw the modal dialog about Windows' Smart Multi-Homed Name Resolution and our Brave-helper-service [ I saw this modal twice in clean profiles, this modal is not shown everytime when VPN is disconnected and connected in win 11, but in win 10 the modal is shown everytime when VPN is disconnected and connected ]

• open Task Manager and ensured Brave VPN Helper service is running under Details tab in task manager when VPN is connected
• ensured BraveberaVpnService is listed under the Service tab in task manager
• ensured Brave VPN Helper is running under background apps when VPN is connected

1. When VPN is connected, the https://www.browserleaks.com/dns doesn't leak the user ISP DNS server as expected
2. When VPN is connected, open brave://settings/security, the Use secure DNS settings is NOT locked by BraveVPN

[stephendonner]

This has been verified on both Windows 10 and Windows 11; marking as QA Pass - Win64.