[Desktop] Gmail image signatures are not loading

[ryanbr]

Description

Signatures images not showing in Gmail

Steps to Reproduce

1. Open Gmail
2. Open settings
3. Scroll down to Signature
4. Create new signature, give it a new name
5. Click on Insert Image
6. Click Upload, Find any image on your PC

Actual result:

Expected result:

Reproduces how often:

Easily, with Shields enabled/default.

Brave version (brave://version info)

Version 1.10.97 Chromium: 83.0.4103.116 (Official Build) (64-bit)

Version/Channel Information:

• Can you reproduce this issue with the current release? Yes
• Can you reproduce this issue with the beta channel? Yes
• Can you reproduce this issue with the dev channel?
• Can you reproduce this issue with the nightly channel? Yes

Other Additional Information:

• Does the issue resolve itself when disabling Brave Shields? Yes (allow all cookies)
• Does the issue resolve itself when disabling Brave Rewards?
• Is the issue reproducible on the latest version of Chrome?

Miscellaneous Information:

As a temp option, Allow all cookies fixes this. Tested referrer issues, not affecting it.

Cookie issues from googleusercontent.com, we should allow cookies on google.com domain.

[LaurenWags]

Verified passed with

Brave | 1.12.94 Chromium: 84.0.4147.89 (Official Build) dev (64-bit)
-- | --
Revision | 19abfe7bcba9318a0b2a6bc6634a67fc834aa592-refs/branch-heads/4147@{#852}
OS | macOS Version 10.14.6 (Build 18G3020)

• Reproduced issue using 1.11.97:

• Upgraded to 1.12.x and confirmed issue resolved:

• Verified STR from description using a clean profile:

---

Verification passed on

Brave | 1.12.94 Chromium: 84.0.4147.89 (Official Build) dev (64-bit)
-- | --
Revision | 19abfe7bcba9318a0b2a6bc6634a67fc834aa592-refs/branch-heads/4147@{#852}
OS | Windows 10 OS Version 1903 (Build 18362.959)

• Reproduced issue using 1.11.97:
  

• Upgraded to 1.12.x and confirmed issue resolved:
  

• Verified STR from description using a clean profile:
  

Verification passed on

Brave	1.12.104 Chromium: 84.0.4147.89 (Official Build) dev (64-bit)
Revision	19abfe7bcba9318a0b2a6bc6634a67fc834aa592-refs/branch-heads/4147@{#852}
OS	Ubuntu 18.04 LTS

• Verified STR from description