This reverts commit f456423cfb820d07bb36e9a8979e3d75cc9d8d76.
This is being reverted because it caused flutter/flutter#45098
(images don't load on iOS).
* Guard against orphaned semantic objects trying to reference a dead bridge on iOS.
* Switched back to a function instead of a macro for checking the bridge.
* Fixed some formatting issues.
When gr context is changed (this happens when sending the app to the background and then to the foreground) we need to update it for all the platform view overlay surfaces.
The update logic was caching the previous gr context to figure if it had to be updated, but after updating it for a given overlay we were updating the cached context. In apps with multiple platform views this will result in overlays with a stale gr context.
This fixesflutter/flutter#36437
And I believe it should fixflutter/flutter#36999 as well (though I don't have repro code to verify).
Having 2 or more platform views simultaneously in the layer tree was crashing immediately on iOS with GL backend.
This regressed in #11070 which passed gl_context to a function in a loop using std::move (which meant on the second iteration the caller is no longer the owner of the field).
I added a scenarios_app test, though this test doesn't run on a physical device on CI so it would have only caught the problem when running locally (flutter/flutter#43852).
Since this is currently only meant to be used by the embedding internally, the setter in Objective-C is only exposed via the FlutterDartProject private class extension. Unit tests have been added to the shell_unittests harness.
Fixes https://github.com/flutter/flutter/issues/37641
Texture unregistration is finished on the GPU thread. The FlutterTexture implementation might not know when it is finished which leads to a race condition. Adding this callback so the FlutterTexture is aware of end of the unregistration process.
Started asserting the FlutterEngine is running before communicating
over channels. This changes a null pointer exception to an
NSException that will provide some meaningful data to clients
incorrectly using the engine in an add-to-app situations.
Made creating and using a FlutterEngine a bit easier, to try to get it get it as easy to use as Android's equivalent.
* Added a default entrypoint variable.
* I added `run` to and `initWithName:` to FlutterEngine.
Manage resource and onscreen contexts using separate IOSGLContext objects.
FlutterView owns the onscreen context, and PlatformViewIOS owns the resource context.
