Use `curly_braces_in_flow_control_structures` for `foundation`, `gestures`, `painting`, `physics` (#104610)

* Use `curly_braces_in_flow_control_structures` for `foundation`

* Use `curly_braces_in_flow_control_structures` for `gestures`

* Use `curly_braces_in_flow_control_structures` for `painting`

* Use `curly_braces_in_flow_control_structures` for `physics`

* fix comments

* remove trailing space

* fix TODO style

* fix deprecated_new_in_comment_reference for `material` library

in a future version of the SDK, these will be flagged, fix them now

* Update pubspec.yaml

* migrates lib/foundation and lib/widgets

* migrates lib/painting and lib/material

* migrates lib/cupertino, lib/gestures, lib/services, lib/semantics and lib/rendering

* fixes failing tests

* migrates test/

* improves hashing of lists

* Call image stream listeners with new flag

* Make _synchronousCall private

* Rename _synchronousCall parameter to be more descriptive and add more documentation

* Rename _hasInitialListeners to _addingInitialListeners and provide a better explanation

* Formatting fix

* Add tests

* Remove dependency on decoration_test.dart

* Simplify tests

* Remove empty line in comment

* Documentation

* Trigger tests

* Trigger tests

* Flip boolean value

* Remove chunk event subscription when disposing a MultiFrameImageStreamCompleter

* Add impl..

* stray prints

This reverts commit d056500b.

This reverts commit 31de052e.

This reverts commit e2490f29.

* Fix single frame image is decoded even cached

* Add MultiFrameImageStreamCompleter decode test for one frame image

My yearly pass to fix spelling errors in the API dartdocs.

* Reland dispose images when done (#67100)

Changes since last time:

- Test for CanvasKit image rendering
  (https://github.com/flutter/flutter/pull/67176)
- Fix CanvasKit dispose impl
  (https://github.com/flutter/engine/pull/21555)
- Update internal google3 customer with a problematic ImageStream
  Listener impl (cl/335091311, cl/335459002)

This reverts commit 473358d9.

* Revert "docs for image disposal (#67066)"

This reverts commit bcb2ac5a.

* Revert "Dispose of images after using them (#66688)"

This reverts commit a7954691.

* Dispose of images after using them
Adds ImageInfo.clone, ImageInfo.dispose, and ImageInfo.isCloneOf.
Makes all stateful holders of ui.Image objects properly clone and dispose of them.
Behavior change for ImageStreamCompleter: Removing the last listener after registering at least one listener results in the object being disposed, and new listeners cannot be added, unless a keepAlive handle is created.
Makes all non-stateful holders of ui.Image (i.e. paintImage and RawImage) assert that whoever gave the image to them has not disposed it on them.

This reverts commit 4518a72f.

* migrate part of painting to nullsafety

* address review comments

* address review comment

* add language version 2.8 in packages/flutter

* enable non-nullable analyzer flag

This converts Diagnosticable to be a mixin instead of an abstract class, so that it can be used to add diagnostics to classes which already have a base class.

It leaves in place the DiagnosticableMixin mixin, since there are some plugins that are still using it, and removing it would mean that those plugins wouldn't work with master branch Flutter anymore. DiagnosticableMixin will be removed once this mixin version of Diagnosticable makes its way to the stable branch.

* Remove listeners for live images when we clear them

* review, more test

* explanation

* Reland "Live image cache" (#51441)

This reverts commit 419a2853.

* Make evict safer