Editor: Changed video recording trim to happen before insertion

[barklund]

Context

This moves the actual trimming of the video recording up so it happens as soon as the user presses "trim", and not only when they press "insert".

Todo

• Make it work!
• Fix bug around re-trimming (partially fixed, see comment below)
• Fix UX around waiting for trim to complete (with a progress bar perhaps?)

User-facing changes

This flow now happens when trimming a new recording - the "cancel trim" button in the footer of course also works.

Testing Instructions

Steps to validate:

1. Start a video recording and record 10+ seconds of video
2. Click the trim button to start trimming the recording
3. Move any trim offset and press trim
4. Observe that trim happens instantly with a dialog informing you of this
5. Wait until trim completes (the shorter the faster)
6. Observe that the displayed video is only the trimmed bit
7. Click the trim button again
8. Observe that the original video is available to trim from, with the previously trimmed bit "preselected"
9. Abort trimming
10. Observe that the original trimmed video still displays correctly
11. Press insert
12. Observe that the trimmed video is uploaded and inserted to the page
13. Observe that the trimmed video has the correct duration and thumbnail

Checklist

• This PR addresses an existing issue and I have linked this PR to it in ZenHub
• I have tested this code to the best of my abilities
• I have verified accessibility to the best of my abilities (docs)
• I have verified i18n and l10n (translation, right-to-left layout) to the best of my abilities
• This code is covered by automated tests (unit, integration, and/or e2e) to verify it works as intended (docs)
• I have added documentation where necessary
• I have added a matching Type: XYZ label to the PR

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Fixes #11988

[swissspidy]

Thanks for working on this 👍

I originally had something simpler in mind without a dialog, but of course I didn't now the technical constraints around this.

Would be good to discuss this with @aaskedall to get his thoughts on this.

[barklund]

I originally had something simpler in mind without a dialog, but of course I didn't now the technical constraints around this.

The dialog is of course only temporary to make it obvious that something is happening in the WIP PR. We should definitely find a better solution.

Would be good to discuss this with @aaskedall to get his thoughts on this.

I plan to once he's back from OOO later today(?).

[barklund]

There is still an annoying bug with re-trimming an already trimmed video (while still in the recording mode). Sometimes the original blob URL doesn't work anymore, like it has been garbage collected (or window.URL.revokeObjectURL has been called), but I don't see why that should happen?

We need to fix this bug, but it's very inconsistent, so it's pretty hard to track down.

[merapi]

We need to reset the last trimming session data, otherwise, you can end up at a dead end (no start/end markers):

The close button should probably work as a cancel button, right now if you don't re-enter the trimming screen before it finishes processing - your video will be lost.

[merapi]

We have the known re-trimming bug and some edge cases to handle - otherwise looks good 👍🏻

[googleforcreators-bot]

Plugin builds for a09ede4 are ready 🛎️!

• Download development build
• Download production build

[barklund]

I'm an idiot!

like it has been garbage collected (or window.URL.revokeObjectURL has been called), but I don't see why that should happen

Maybe because it has been revoked right here? 🤦 Well, I guess this fixes it though

[barklund]

I didn't actually reset the trim info in the reset function, so that's why it didn't work correctly.