The Info.plist override was missed earlier.
The main changes to the tests are due to the UI thread merge with the platform thread. The amendment to the "spawn" API are due to the fact that the assertions checked for the presence of GrDirectContext which will never exist with Impeller.
Unblocks https://github.com/flutter/engine/pull/56706
I found this while migrating `FlutterPlatformViews_Internal.mm` to ARC https://github.com/flutter/engine/pull/52535. I'll land this first.
```objc
if (_backdropFilterView != visualEffectView) {
_backdropFilterView = [visualEffectView retain];
}
```
should instead be something like:
```objc
if (_backdropFilterView != visualEffectView) {
id oldBackdropFilterView = _backdropFilterView;
_backdropFilterView = [visualEffectView retain];
[oldBackdropFilterView release];
}
```
But that's already what the built-in MRC `nonatomic, retain` property setter does, so use that instead.
Added a test that passes on this PR and fails on main.
Generated by https://github.com/flutter/engine/pull/48903 (`dart ./tools/header_guard_check/bin/main.dart --fix`).
As discussed with @cbracken and @jmagman, the guards are not technically needed on the Mac/iOS code, but they (a) do not hurt and (b) still provide value if for some reason `#include` is used instead of `#import` (though I suspect we could try to add that to the tool in the future as well).
Save a recording/screenshot to the uploaded xcresult when a Scenario test fails.
<img width="1052" alt="Screenshot 2023-12-14 at 6 34 47â¯PM" src="https://github.com/flutter/engine/assets/682784/c1294497-28f6-4400-b21c-da689a224dc4">
<img width="244" alt="Screenshot 2023-12-14 at 6 41 03â¯PM" src="https://github.com/flutter/engine/assets/682784/f769dd5f-a71b-4320-b9ef-64eac722166a">
No more errant spew as reported in https://github.com/flutter/engine/pull/19668 when this was originally turned off.
```
Test Case '-[StatusBarTest testTapStatusBar]' started.
t = 0.00s Start Test at 2023-12-14 18:20:34.207
...
t = 2.69s Synthesize event
t = 2.70s Find the StatusBar at {{0.0, 0.0}, {375.0, 20.0}}
t = 2.72s Find the StatusBar at {{0.0, 0.0}, {375.0, 20.0}}
t = 2.74s Find the StatusBar at {{0.0, 0.0}, {375.0, 20.0}}
t = 3.03s Wait for com.apple.springboard to idle
t = 3.43s Waiting 1.0s for "0,PointerChange.add,device=0,buttons=0,signalKind=PointerSignalKind.none" TextField to exist
t = 4.43s Checking `Expect predicate `exists == 1` for object "0,PointerChange.add,device=0,buttons=0,signalKind=PointerSignalKind.none" TextField`
t = 4.43s Checking existence of `"0,PointerChange.add,device=0,buttons=0,signalKind=PointerSignalKind.none" TextField`
t = 4.45s Capturing element debug description
t = 4.45s Checking existence of `"0,PointerChange.add,device=0,buttons=0,signalKind=PointerSignalKind.none" TextField`
/Volumes/Work/s/w/ir/cache/builder/src/out/ios_debug_sim/scenario_app/Scenarios/ScenariosUITests/StatusBarTest.m:37: error: -[StatusBarTest testTapStatusBar] : ((exists) is true) failed
t = 4.48s Tear Down
```
https://logs.chromium.org/logs/flutter/buildbucket/cr-buildbucket/8761683198070320113/+/u/test:_Scenario_App_Integration_Tests__3_/stdout
Fixes https://github.com/flutter/flutter/issues/140192
[C++, Objective-C, Java style guides]: https://github.com/flutter/engine/blob/main/CONTRIBUTING.md#style
This PR implements `FlutterMetalLayer`, a drop-in (as far as Flutter is
concerned) replacement for `CAMetalLayer`. The biggest difference is
that `FlutterMetalLayer` can present frames from background thread
within a `CATransaction`.
`FlutterMetalLayer` is disabled by default. To opt-in, add the following
item to `Info.plist`:
```xml
<key>FLTUseFlutterMetalLayer</key>
<true/>
```
The performance seems quite good, consistent 120hz on iPhone 13 Pro.
Benefits
- presenting with transaction from background thread, which, down the
line, would allow for platform views without thread merging.
- fine control over how the surface is displayed - we can display single
surface on multiple `CALayers`, each showing different part, allowing
for performant implementation of unobstructed platform views.
Drawbacks
- this not being a metal layer makes working with metal instrument tools
more awkward
As part of eliminating the Flutter buildroot
(https://github.com/flutter/flutter/issues/67373), we are moving all
third-party dependencies from //third_party to //flutter/third_party.
Once all third-party dependencies have been migrated, tooling and config
will be moved and the buildroot will be eliminated altogether.
No tests changed because there is no semantic change to this PR. This is
simply relocating a dependency.
This PR moves expat, ocmock, libjpeg-turbo, libwebp, and wuffs to
//flutter/third_party.
It also deletes //third_party/fontconfig, which was unused.
