iOS blank screen when opened from external app in 1.62+

[iccub]

Description:

Steps to Reproduce

1. Open an url from a 3rd party app

Actual result:

blank screen shows, the site does not load until you hit reload button

Expected result:

Reproduces how often: [Easily reproduced, Intermittent Issue]

Brave Version:

• Can you reproduce this issue with the most recent build from TestFlight?
• Can you reproduce this issue with the previous version of the current build from TestFlight?
• Can you reproduce this issue with the current build from AppStore?

Device details:

Website problems only:

• Does the issue resolve itself when disabling Brave Shields?
• Is the issue reproducible on the latest version of Mobile Safari?

Additional Information

[cuba]

When loading the default engine during startup on slow devices this may add an additional 10 seconds to load the first page. On newer devices this is more like 4-5 seconds. I'm not sure if this is the "white page" people are referring to. Certainly the screen is white during this period. But nothing "hangs" but rather adds a delay.

If we don't load this engine, anyone opening pages such as YouTube will encounter ads, trackers etc until they reload the page. (note for pages like YouTube, navigating will not fix this. A reload is necessary)

However there are some ideas out there which we will work on on how to deal with this delay:

1. Using dat files during launch which seems to make compile times a little over 2x faster.
2. If the above is not enough we might consider using a slimmed down version of the rules for launch purposes.

Note: We still don't even preload other filter lists such as cookie consent. Ideally we would preload all the enabled filter lists too so the user doesn't encounter things like cookie consent notices, open in app notices, etc during launch. But seeing as we are having launch problems with just the default filter list, this is unlikely to happen in the short run.

[iccub]

This happens when the app is foreground as well. We have at least 1 report with a recording showing app is running already

[cuba]

Here are some usual launch metrics on an iPhone 8. Notice the ~9s launch delay which clearly (and intentionally) delays the first page load.

[cuba]

This happens when the app is foreground as well. We have at least 1 report with a recording showing app is running already

Then i'm not sure if this is the cause of this issue. Not saying it's not Adblock related (I don't know) but something completely different than the launch tasks are casing it.

[cuba]

Actually one possibility is that a newly updated filter list is downloaded and compiled during navigation. Notice how the additional filter lists still delay the subdocument page loads in the screenshot above. I can easily play with the priorities to make these downloaded tasks happen after the page load as seen here:

Notice how the subdocuments (decidePolicyFor:WKNavigationAction row) are loaded much faster and before the filterList(omo...) (compileEngine row) task

[mihaiplesa]

Happens to me and a friend as well.

[iccub]

This is fixed and please give it a try in build 1.63 - not live yet in the app store. https://github.com/brave/brave-core/pull/22343

They delay Jacob mentions is separate issue