Modify postinstall script to allow non-release channel builds to inject referral codes into browser state for osx

[aekeus]

Test plan

See brave/brave-core#2549

Description

Please modify the postinstall script to allow non-release channel builds to inject referral codes into browser state for osx.

[aekeus]

cc @bsclifton @emerick @simonhong

[bsclifton]

Checking this out now...

[bsclifton]

Fix completed, ready for review 😄
brave/brave-core#2549

[btlechowski]

It seems to be macOS only issue. I added the proper label.

[LaurenWags]

Verified passed with

Brave 0.67.112 Chromium: 76.0.3809.62 (Official Build) beta (64-bit)
Revision 7b77856b3aa34d72f246d12340fc1ded8b2c0e83-refs/branch-heads/3809@{#798}
OS Mac OS X

• Verified test plan from Update macOS postinstall script to properly build executable paths brave-core#2549, verified promo code in promoCode file and on brave://local-state

Brave 0.68.104 Chromium: 75.0.3770.100 (Official Build) dev (64-bit)
Revision cd0b15c8b6a4e70c44e27f35c37a4029bad3e3b0-refs/branch-heads/3770@{#1033}
OS Mac OS X

• Verified test plan from Update macOS postinstall script to properly build executable paths brave-core#2549, verified promo code in promoCode file and on brave://local-state

Brave 0.69.77 Chromium: 76.0.3809.62 (Official Build) nightly (64-bit)
Revision 7b77856b3aa34d72f246d12340fc1ded8b2c0e83-refs/branch-heads/3809@{#798}
OS Mac OS X

• Verified test plan from Update macOS postinstall script to properly build executable paths brave-core#2549, verified promo code in promoCode file and on brave://local-state

cc @kjozwiak for a second check on macOS

[kjozwiak]

Verification PASSED on macOS 10.14.5 x64 using the following builds:

Installed 0.70.6 Chromium: 76.0.3809.62 via Brave-Browser-Nightly-RED194.pkg and ensured the following

• ~/Library/Application\ Support/BraveSoftware/Brave-Browser-Nightly/promoCode was created
• promoCode displayed RED194
• promoCode was removed when starting 0.70.6 Chromium: 76.0.3809.62
• "promo_code": "RED194" was visible under brave://local-state

Installed 0.69.91 Chromium: 76.0.3809.62 via Brave-Browser-Dev-KAM253.pkg and ensured the following

• ~/Library/Application\ Support/BraveSoftware/Brave-Browser-Dev/promoCode was created
• promoCode displayed KAM253
• promoCode was removed when starting 0.69.91 Chromium: 76.0.3809.62
• "promo_code": "KAM253" was visible under brave://local-state

Installed 0.68.109 Chromium: 76.0.3809.62 via Brave-Browser-Dev-KAM159.pkg and ensured the following

• ~/Library/Application\ Support/BraveSoftware/Brave-Browser-Dev/promoCode was created
• promoCode displayed KAM159
• promoCode was removed when starting 0.68.109 Chromium: 76.0.3809.62
• "promo_code": "KAM159" was visible under brave://local-state

Installed 0.67.117 Chromium: 76.0.3809.62 via Brave-Browser-BRA194.pkg and ensured the following

• ~/Library/Application\ Support/BraveSoftware/Brave-Browser/promoCode was created
• promoCode displayed BRA194
• promoCode was removed when starting 0.67.117 Chromium: 76.0.3809.62
• "promo_code": "BRA194" was visible under brave://local-state