Add `Keep in dock` option to first run dialog and settings

Description

When user sets Brave as a default browser, “Keep Brave in dock” also.

Steps to Reproduce

1. Launch Brave with clean profile
2. Click Set Brave as default button after checking Keep in dock
3. Check Brave is added to dock
4. Load brave://settings/getStarted and check settings shows as Brave is already in dock
5. Unpin from taskbar and reload brave://settings/getStarted and click Dock button
6. Check Brave is added to dock

Brave version (brave://version info)

Version/Channel Information:

• Can you reproduce this issue with the current release? n/a
• Can you reproduce this issue with the beta channel? n/a
• Can you reproduce this issue with the nightly channel? n/a

Other Additional Information:

• Does the issue resolve itself when disabling Brave Shields? n/a
• Does the issue resolve itself when disabling Brave Rewards? n/a
• Is the issue reproducible on the latest version of Chrome? n/a

Miscellaneous Information:

See related: https://github.com/brave/brave-browser/issues/24054

[sangwoo108]

I guess chrome/browser/mac/dock.h can be used for this

[stephendonner]

Verification PASSED using

Brave	1.46.96 Chromium: 107.0.5304.91 (Official Build) beta (x86_64)
Revision	3d5948960d62418160796d5831a4d2d7d6c90fa8-refs/branch-heads/5304@{#1097}
OS	macOS Version 11.7.1 (Build 20G918)

Prerequisite: make a non-Brave browser the system default via Apple menu -> System Preferences... -> General -> Default web browser

Case 1: Pin Brave to dock via the Pin to Dock checkbox in the first-run dialog - PASSED

1. installed 1.46.96
2. launched Brave
3. checked the Keep in Dock checkbox
4. clicked on the Set Brave as default button
5. confirmed I got the Do you want to change your default web browser to "Brave" or keep using "Firefox"? dialog
6. clicked on Use "Brave"
7. confirmed Brave is kept in the dock
8. closed Brave
9. relaunched by clicking on the Brave icon in the dock
10. opened brave://settings/getStarted
11. confirmed Brave is your default browser text
12. confirmed Brave is already in Dock text

Confirmed Brave is successfully kept in the dock

step 3	step 5	step 7	steps 11-12

Case 2: Unpin Brave from the dock and Pin to Dock it from brave://settings/getStarted - PASSED

1. continued from Case 1, with Brave kept in the dock
2. context-clicked on Brave and chose Options -> Keep in Dock
3. reloaded brave://settings/getStarted
4. confirmed the Dock button beside Keep in Dock is clickable
5. clicked Dock
6. confirmed I now saw Brave is already in Dock
7. context-click on Brave

Confirmed Brave is docked and shows Options -> Keep in Dock enabled

step 4	step 6	step 7

Case 3: With Pin to Dock unchecked (default), click Set Brave as default on the first-run dialog - PASSED

1. installed 1.46.96
2. launched Brave
3. left Keep in Dock unchecked (default)
4. click Set Brave as default button
5. clicked Use "Brave" on the next dialog
6. clicked Skip welcome tour
7. opened brave://settings/getStarted
8. confirmed Brave is your default browser text is shown
9. confirmed Dock button is shown in next to Keep in Dock
10. clicked on the Dock button
11. confirmed the Dock button on brave://settings/getStarted disappears
12. context-click on Brave

Confirmed Brave is docked and shows Options -> Keep in Dock enabled

step 4	step 5	step 8-9	step 11	step 12

Case 4: Pin to Dock Brave via brave://settings/getStarted when a non-Brave browser is set as default via Apple menu’ -> System Preferences -> General Default web browser - PASSED

1. installed 1.46.96
2. launched Brave
3. clicked Maybe later
4. clicked Skip welcome tour
5. closed Brave
6. relaunched Brave
7. clicked on Set as default in the infobar
8. clicked on Use "Brave"
9. opened brave://settings/getStarted
10. confirmed it read Brave is your default browser
11. confirmed the Dock button is enabled
12. clicked on the Dock button
13. confirmed the Dock button disappeared
14. confirmed it read Brave is already in Dock
15. context-clicked Brave

Confirmed Brave is docked and shows Options -> Keep in Dock enabled

step 3	step 7	step 8	steps 10-11	steps 13-14	step 15

Case 5: Upgrade from 1.45.100 (beta) -> 1.46.96 (beta) - PASSED

1. installed 1.45.100
2. launched Brave
3. clicked Set Brave as default on the first-run dialog
4. clicked Use "Brave"
5. opened brave://settings/getStarted and confirmed it shows Brave is your default browser text
6. upgraded to 1.46.96
7. opened brave://settings/getStarted
8. clicked the Dock button
9. confirmed the Dock button disappeared, and the text now reads "Brave is already in Dock`
10. context-clicked Brave

Confirmed Brave is docked and shows Options -> Keep in Dock enabled

step 3	step 4	step 5	step 8	step 9	step 10