Reland enable DisplayList by default

[flar]

No description provided.

[gw280]

I'm a little out of the loop, but how confident are we in the test coverage for this?

[chinmaygarde]

but how confident are we in the test coverage for this?

I am adequately confident with the coverage in #26928. This was also attempted once before and findings have been incorporated into fixes in the engine.

[flar]

I think it has survived the engine post-submit tests and the framework roll, except that I think there is an outstanding issue with the framework tests were the SVG tests do some golden tests that require exact results and we end up with some +/-1 errors. I was asking @dnfield about adjusting those SVG golden tests to have a build-in epsilon for comparison, but I don't think that conversation was resolved.

[dnfield]

In the past what we've done is just update the goldens in flutter_svg - is there some reason we can't do that now?

[flar]

In the past what we've done is just update the goldens in flutter_svg - is there some reason we can't do that now?

If this were guaranteed to stick all the way up the pipeline then we might do that, but we may eventually perform similar optimizations as SkPicture used to do and so the rendering may fluctuate even if this PR does stick. Expect some volatility here over the next few weeks.

[flar]

@dnfield dnfield/flutter_svg#575

[flar]

Waiting to land: flutter/tests#116