Michael Goderbauer 136f4a03c4 Dynamic view sizing [dart:ui] (flutter/engine#48090)
Towards https://github.com/flutter/flutter/issues/134501.

This PR makes the following changes to the public dart:ui API:

* It adds the `FlutterView.pysicalConstraints` property that describes max and min width and height for a view. The framework is allowed to size the `FlutterView` to any `Size` that meets these constraints.
* It adds an optional `size` argument to `FlutterView.render`. The framework provides the chosen `Size` that meets the aforementioned constraints to the `render` method. If the `FlutterView.pysicalConstraints` are tight (minHeight == maxHeight and minWidth == maxWidth) the argument is optional to remain backwards compatible. In all other cases, a `Size` must be provided.
* It adds a `ViewConstraints` class, which is basically the `dart:ui` version of `BoxConstraints` (This is similar to how we have `ViewPadding` in dart:ui to mirror `EdgeInsets` from the framework). It describes the constraints of a `FlutterView`, i.e. it powers the `FlutterView.pysicalConstraints` property.

This change does not wire anything up to the embedders. For now, `FlutterView.pysicalConstraints` just returns tight constraints for the embedder-provided size of the view (`FlutterView.physicalSize`) and the size provided to `FlutterView.render` is ignored (after it is checked that it meets the constrains). 

This PR enables the framework to implement the new dynamic view sizing and embedders to separately expose the new functionality to their clients.

Presubmits will fail until https://github.com/flutter/flutter/pull/138565 is submitted to the framework.

**DO NOT SUBMIT until https://github.com/flutter/flutter/pull/138648 is ready.**
2023-11-27 22:33:59 +00:00
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