stuartmorgan

I'm making this a draft just to get it off of the review queue; please mark it as ready for review once you've had a chance to update. Thanks!

@tarrinneal to adopt, per triage meeting.

I'm exploring an alternate solution for making deprecation warnings errors now; if that pans out I'll have a PR soon to enable it with an initial exclusion list, and then...

> I'm exploring an alternate solution for making deprecation warnings errors now; if that pans out I'll have a PR soon to enable it with an initial exclusion list, and...

I'm definitely not a Java expert, but I think for a use case like `CameraFeatures`'s `featureMap` you need `CameraFeatures` rather than `CameraFeatures`.

> What release is this fix available in? You can look at [the pubspec changes in a PR](https://github.com/flutter/packages/pull/3273/files#diff-2d52b2f7f5cade86264e5d4a9e40b52a90d78eef1b38af8914c90a822d238bd1R5) to know what version it is in.

Capturing from the other issue for ease of reviewing: this is a reland with changes of a previously reviewed/landed/reverted PR. The diffs relative to the original reverted PR are at...

Also, should remember this time to have one of us push a commit here to trigger the FTL tests in presubmit.

Or I can just do it myself right now so we don't forget :)

Third-party package dependencies are a liability for us in the longer term, so we avoid them unless there's really no other option. In this case, since the SDK switch logic...