Fixes https://github.com/flutter/flutter/issues/65258
The following devicelab tests should pass after this patch:
- flutter_gallery_sksl_warmup__transition_perf_e2e_ios32
- flutter_gallery_sksl_warmup_ios32__transition_perf
Lazy async stacks were already enabled by-default in AOT mode in [0] - which made the
gen_snapshot invocations use "--lazy-async-stacks --no-causal-async-stacks".
This change does the same with the engine defaults, which makes this be enabled
by-default in JIT mode as well.
See go/dart-10x-faster-async for more information.
This is a re-land: A fix for what we believe to have caused the last revert has landed upstream in Dart in dart-lang/sdk@0004589
[0] flutter/flutter@3478232
## Description
As the related issue refer, the application may be doing too much work on its main thread even in a simple hello_world demo.
That is because the creation of `Engine` on the ui thread takes a noticeable time, and it is blocking the platform thread in order to run `Shell::Setup` synchronously.
The cost of `Engine`'s constructor is mainly about the creating of root isolate. Actually, there used to be another time-consuming process, the default font manager setup, which was resolved by https://github.com/flutter/engine/pull/18225.
Similar to https://github.com/flutter/engine/pull/18225, this pr move the creation of root isolate out from creating `Engine`. After this action, the main thread blocking is quite an acceptable slice.
## Related Issues
https://github.com/flutter/flutter/issues/40563 could be resolved by this pr.
This is a Fuchsia-only shell test, confirming that when the timezone
setting is changed on the realm via Fuchsia's FIDL interface
`fuchsia.settings.Intl`, the Dart isolate running in that realm receives
the change and starts reporting the appropriate timestamp.
We already have a [similar test][tst] that verifies the timezones in the
dart VM matches the local timezone at start, but there was no test that
also verified timezone changes.
[tst]: https://github.com/flutter/engine/blob/master/shell/common/shell_unittests.cc#L1166
See issue #61284
Reland #19396 with a fix for improper scale that was affecting internal tests
Tested: Ran all unittests, ran internal tests, and ran workstation on Fuchsia
BUG: 53062, 53063
The fuchsia code around metrics and sizing was just sending this
information through a side-channel, when the engine already had the
information available. So, delete all of it to make future CLs simpler.
Additionally, the SceneUpdateContext has many unneccesary dependencies
re: metrics and PaintTasks. Break those to make future CLs simpler.
Tested: Ran all unittests and ran workstation on Fuchsia
BUG: 53062, 53063
