05036058d7
This PR fixes https://github.com/flutter/flutter/issues/112202. `Scene` is no longer tied to views, but receives method arguments for view properties, clearing the path to multiview Flutter. `Scene` no longer creates a `LayerTree` on construction, but only part of the config. When a output method is called (`toImage`, `toImageSync`, or `takeLayerTree`), the `LayerTree` is constructed on the spot. In this way, all `LayerTree`s return to being `unique_ptr`s instead of `shared_ptr`s, reverting part of https://github.com/flutter/engine/pull/35608 . And `Scene` no longer needs to disfunction after one `takeLayerTree`, since the layer tree config is never really taken away. A `device_pixel_ratio` is now added to the parameter list of `Engine::Render` and `Animator::Render`. ## Pre-launch Checklist - [x] I read the [Contributor Guide] and followed the process outlined there for submitting PRs. - [x] I read the [Tree Hygiene] wiki page, which explains my responsibilities. - [x] I read and followed the [Flutter Style Guide] and the [C++, Objective-C, Java style guides]. - [x] I listed at least one issue that this PR fixes in the description above. - [ ] I added new tests to check the change I am making or feature I am adding, or Hixie said the PR is test-exempt. See [testing the engine] for instructions on writing and running engine tests. - [x] I updated/added relevant documentation (doc comments with `///`). - [x] I signed the [CLA]. - [x] All existing and new tests are passing. If you need help, consider asking for advice on the #hackers-new channel on [Discord]. <!-- Links --> [Contributor Guide]: https://github.com/flutter/flutter/wiki/Tree-hygiene#overview [Tree Hygiene]: https://github.com/flutter/flutter/wiki/Tree-hygiene [Flutter Style Guide]: https://github.com/flutter/flutter/wiki/Style-guide-for-Flutter-repo [C++, Objective-C, Java style guides]: https://github.com/flutter/engine/blob/main/CONTRIBUTING.md#style [testing the engine]: https://github.com/flutter/flutter/wiki/Testing-the-engine [CLA]: https://cla.developers.google.com/ [flutter/tests]: https://github.com/flutter/tests [breaking change policy]: https://github.com/flutter/flutter/wiki/Tree-hygiene#handling-breaking-changes [Discord]: https://github.com/flutter/flutter/wiki/Chat