fix(tabs): preserve scroll position when switching between tabs

[crisbeto]

Preserves the scroll position when switching between tabs. Previously it was being reset to 0, because we detach and re-attach the content.

Fixes #6722.

[jelbourn]

@crisbeto @andrewseguin should we revisit this or close?

[crisbeto]

I think it's still a valid issue, but I haven't gotten around to finding an Android phone to test the issue that @andrewseguin mentioned.

[jelbourn]

AFAIK Chrome dev tools should mimic Android Chrome pretty well. Was it not reproducible there?

[crisbeto]

AFAIK the Chrome dev tools only resize the viewport, simulate touch events and fake the user agent.

[josephperrott]

@crisbeto Please rebase when you have a chance.

[crisbeto]

Rebased.

[ngbot[bot]]

Hi @crisbeto! This PR has merge conflicts due to recent upstream merges. Please help to unblock it by resolving these conflicts. Thanks!

[andrewseguin]

Hey @crisbeto - if you don't mind rebasing, we can try to get this pushed in

[crisbeto]

It's good to go now @andrewseguin.

[andrewseguin]

Also, do you mind adding in this example to the Material Examples? We don't currently have a good example of scrolling content in our tabs and it can be used to double-check the functionality

https://stackblitz.com/edit/angular-vtgxfn?file=main.ts

[crisbeto]

Done @andrewseguin.

[deftomat]

Any news?

[jelbourn]

(revisiting old PRs) Keeping this one open since we still want to land it, but still lower priority than other issues.