crash when opening/scrolling through particular PDF

[kjozwiak]

Description:

Originally reported by @pes10k via Slack, Brave will crash when loading and scrolling through the following PDF:

https://static1.squarespace.com/static/57338e2c04426238cff175c6/t/60c9462f924a473dc95dc850/1623803439283/ListaDeVinos...pdf

Steps to Reproduce

1. open the PDF mentioned above
2. once loaded, start scrolling and you'll eventually crash the Brave

Actual result:

Brave crashes when you open the above PDF and either leave it opened for a few seconds or start scrolling through the PDF.

Expected result:

Brave shouldn't be crashing.

Reproduces how often: [Easily reproduced, Intermittent Issue]

100% reproducible using the STR/Cases mentioned above.

Brave Version:

• 1.27.1 (21.6.22.16) - Reproduced
• 1.28 (21.7.5.14) - Reproduced

Device details:

• iPhone 11 running iOS 14.6 - Reproduced

Website problems only:

• did you check with Brave Shields down? N/A
• did you check in Safari/Firefox (WkWebView-based browsers)? N/A

[kylehickinson]

Duplicate of #3868