support recording canvas in iframe and shadow dom

[p-mazhnik]

Resolves #1412, resolves #1081

Before

Red square is on the main page;
Green is inside the shadow dom on the main page;
Blue one is within the iframe;
Pink is inside the shadow dom within the iframe.

canvas-iframe-before.mov

After

canvas-iframe-after.mov

Key differences from existing PRs:

• support for sampling: 'all' mode
• ShadowDomManager is utilized for obtaining information about the shadow DOMs, rather than looping through all the elements on the page
• support for exiting takeCanvasSnapshots loop on reset
• tests

[changeset-bot]

🦋 Changeset detected

Latest commit: db60778

The changes in this PR will be included in the next version bump.

This PR includes changesets to release 8 packages

Name	Type
rrweb	Patch
rrweb-snapshot	Patch
rrdom	Patch
rrdom-nodejs	Patch
rrweb-player	Patch
@rrweb/types	Patch
@rrweb/web-extension	Patch
rrvideo	Patch

Not sure what this means? Click here to learn what changesets are.

Click here if you're a maintainer who wants to add another changeset to this PR

[EnzoPortela]

It still working?

[ptang-nr]

Hello, we are using rrweb and it's been a great product for capturing replays! We have also come across edge cases where we are not capturing <canvas> elements from shadow DOMS and we're greatly interested in utilizing the fix implemented within this PR.

It looks like this PR has been "stuck" in the current state for the last 6 months. What is the next step to move forward with this? Is it awaiting merge conflict resolution by original author or would it be ok if we or others try to help resolve the conflict?

(Asking as I'm still new to open source and not sure about etiquette, thanks for your consideration!)
@p-mazhnik @okejminja @Juice10

[GOSPDigitalAssets]

We're also waiting for this PR approval as we'd like to use rrweb with flutter canvaskit too. Hope it will be merged soon!