Description

Before this change, ScrollService attempted to scroll down immediately after navigating, before before the page had fully loaded.
I considered making the Table component (and other data-loading componets) responsible for telling the ScrollService that data has been loaded—or to use Angular's Route.resolve property, but realized that using ResizeObserver to get the page size is a lot more reliable (and a small code change overall, so less painful 😁).

I'm pretty sure there is some way to use RxJS observables for the unhandledScrollEvent variable I added, but I couldn't figure out a good way to do so. (Perhaps combineLatestAll with something to mark an event as "handled", but that "something" has been a bit elusive.) Would appreciate any pointers in that regard.

Also, with the unhandled event approach, there is a chance that if only part of a page loads (or perhaps, if the page loads with a smaller size than the one it had when it was stored in history), the user might start interacting with the page, and trigger the unhandled event much later, in case something resizes the page to be tall enough.

Related issues

Fixes #7097.

To reproduce the issue, I would:

1. Scroll down on the My Videos page.
2. Open a video's "Manage" button
3. Switch the connection in Firefox's Dev Tools / Network to Throttled (otherwise, reproducing on localhost is near impossible)
4. Press the back button on the browser

Has this been tested?

• 👍 yes, I added tests to the test suite
• 💭 no, because this PR is a draft and still needs work
• 🙅 no, because this PR does not update server code
• 🙋 no, because I need help