Deploy Quad9 DoH pilot test in 50% of Nightly clients

[arthuredelstein]

No description provided.

[LaurenWags]

LGTM 👍 Merging into main/staging so we can verify before pushing #1009 into production.

[LaurenWags]

macOS arm64 verifications

Quick note: The functionality of the feature was QA'd/verified more thoroughly via brave/brave-browser#35677 as per brave/brave-browser#35677 (comment), brave/brave-browser#35677 (comment), brave/brave-browser#35677 (comment), and brave/brave-browser#35677 (comment).

Nightly

Verification PASSED on macOS arm64 using the following build(s):

Brave	1.67.38 Chromium: 124.0.6367.60 (Official Build) nightly (arm64) 
Revision	8443e06be07e56a517b68619babde4d5b8282630
OS	macOS Version 14.5 (Build 23F5049f)

BraveFallbackDoHStudy:Enabled

• installed 1.67.x and started Brave using the following
  • --enable-logging=stderr --variations-server-url=https://variations.bravesoftware.com/seed and relaunched using same command line arg
• ensured that BraveFallbackDoHStudy:Enabled is visible under brave://version
• navigated to brave://settings/security and ensured that "Select DNS provider" showed "OS default or Quad9"
• navigated to https://on.quad9.net/ and confirmed page shows as "You ARE using quad9" as expected

Example	Example	Example

BraveFallbackDoHStudy:Default

• installed 1.67.x and started Brave using the following
  • --enable-logging=stderr --variations-server-url=https://variations.bravesoftware.com/seed and relaunched using same command line arg
• ensured that BraveFallbackDoHStudy:Default is visible under brave://version
• navigated to brave://settings/security and ensured that "Select DNS provider" showed "OS default (when available)"
• navigated to https://on.quad9.net/ and confirmed page shows as "You are NOT using quad9" as expected

Example	Example	Example

BETA

Verification PASSED on macOS arm64 using the following build(s):

Brave	1.66.90 Chromium: 124.0.6367.82 (Official Build) beta (arm64) 
Revision	803a4c629341791205b744969c48b8da9f2cfa4d
OS	macOS Version 14.5 (Build 23F5049f)

BraveFallbackDoHStudy not enabled/visible via brave://version

• launched/re-launched 1.66.90 Chromium: 124.0.6367.82 using --enable-logging=stderr --variations-server-url=https://variations.bravesoftware.com/seed
• ensured that BraveFallbackDoHStudy isn't visible via brave://version

Release

Verification PASSED on macOS arm64 using the following build(s):

Brave	1.65.122 Chromium: 124.0.6367.82 (Official Build) (arm64) 
Revision	64099bd820a06a2843326660372e895b7d78f20b
OS	macOS Version 14.5 (Build 23F5049f)

BraveFallbackDoHStudy not enabled/visible via brave://version

• launched/re-launched 1.65.122 Chromium: 124.0.6367.82 using --enable-logging=stderr --variations-server-url=https://variations.bravesoftware.com/seed
• ensured that BraveFallbackDoHStudy isn't visible via brave://version

[LaurenWags]

Android ARM x64 verifications using Pixel 3 XL with Android 12

Quick note: The functionality of the feature was QA'd/verified more thoroughly via brave/brave-browser#35677 as per brave/brave-browser#35677 (comment).

Nightly

Verification PASSED on Android ARM x64 using the following build(s):

Brave	1.67.42 Chromium: 124.0.6367.82 (Official Build) canary (32-bit)
Revision	20596bca72f42301946d544fe158cb4e1aa7a70a
OS	Android 12; Build/SP1A.210812.016.C1; 31; REL

BraveFallbackDoHStudy:Enabled

• Disabled wifi and installed 1.67.x
• Launched Brave Nightly
• Navigated to Developer Options > QA Prefs > Entered command line string:
  • --enable-logging=stderr --variations-server-url=https://variations.bravesoftware.com/seed
• Relaunched as directed
• Closed browser, enabled wifi, relaunched a couple times until the seed was populated under brave://version
• ensured that BraveFallbackDoHStudy:Enabled is visible under brave://version
• navigated to Three-dot menu > Settings > Brave Shields & privacy > Use secure DNS and ensured that "Use your current service provider or Quad9" was selected
• navigated to https://on.quad9.net/ and confirmed page shows as "You ARE using quad9" as expected

Example	Example	Example

BraveFallbackDoHStudy:Default

• Disabled wifi and installed 1.67.x
• Launched Brave Nightly
• Navigated to Developer Options > QA Prefs > Entered command line string:
  • --enable-logging=stderr --variations-server-url=https://variations.bravesoftware.com/seed
• Relaunched as directed
• Closed browser, enabled wifi, relaunched a couple times until the seed was populated under brave://version
• ensured that BraveFallbackDoHStudy:Enabled is visible under brave://version
• navigated to Three-dot menu > Settings > Brave Shields & privacy > Use secure DNS and ensured that "Use your current service provider" was selected
• navigated to https://on.quad9.net/ and confirmed page shows as "You are NOT using quad9" as expected

Example	Example	Example

BETA

Verification PASSED on Android ARM x64 using the following build(s):

Brave	1.66.90 Chromium: 124.0.6367.82 (Official Build) beta (32-bit)
Revision	803a4c629341791205b744969c48b8da9f2cfa4d
OS	Android 12; Build/SP1A.210812.016.C1; 31; REL

BraveFallbackDoHStudy not enabled/visible via brave://version

• Disabled wifi and installed 1.66.x
• Launched Brave Beta
• Navigated to Developer Options > QA Prefs > Entered command line string:
  • --enable-logging=stderr --variations-server-url=https://variations.bravesoftware.com/seed
• Relaunched as directed
• Closed browser, enabled wifi, relaunched a couple times until the seed was populated under brave://version
• ensured that BraveFallbackDoHStudy isn't visible via brave://version

Release

Verification PASSED on Android ARM x64 using the following build(s):

Brave	1.65.122 Chromium: 124.0.6367.82 (Official Build) (32-bit)
Revision	64099bd820a06a2843326660372e895b7d78f20b
OS	Android 12; Build/SP1A.210812.016.C1; 31; REL

BraveFallbackDoHStudy not enabled/visible via brave://version

• Disabled wifi and installed 1.65.x
• Launched Brave
• Navigated to Developer Options > QA Prefs > Entered command line string:
  • --enable-logging=stderr --variations-server-url=https://variations.bravesoftware.com/seed
• Relaunched as directed
• Closed browser, enabled wifi, relaunched a couple times until the seed was populated under brave://version
• ensured that BraveFallbackDoHStudy isn't visible via brave://version