Add code example for CustomScrollView on how to make it grow in two directions along its scroll axis (#57670)

* Have _warpToCurrentIndex() shortcut logic behave properly

* Add test

* Apply code review

* Fix typo (fromm -> from)

Re-adds a line that was accidentally removed in #57515

Co-authored-by: Jenn Magder <magder@google.com>

This reverts commit 602d8baf.

* move pending timers list code out of assert

* style change
Co-authored-by: Emmanuel Garcia <egarciad@google.com>

* add unit tests

* formatting

* pending timer test

* pending timer assertion test

* add setup and teardown
Co-authored-by: Emmanuel Garcia <egarciad@google.com>

Reland: #56167

 For files larger than 250 KB (roughly the size of framework.dart), chunk the conversion. This may be important for large assets like images.

The Linux CMakeLists.txt are intended to be compatible with 3.10, but
accedintally used a list construct that wasn't added until 3.12. This
adds a custom replacement function.

This makes the build compatible with 3.10 as originally intended.

* Value Indicator uses Global position when calculating horizontal position

* fixed test

* fixed analyzer

* Made globalCenter variable and added comments

- OsError now implements exception, remove workaround.
- Prefer is check to catching TypeError

Treats 'pluginClass: none' as equivalent to having no 'pluginClass'
entry on the desktop platforms, to satisy stable channel plugin
validation of Dart-only desktop plugin implementations. See
issue for full details.

Part of https://github.com/flutter/flutter/issues/57497

* Bump flutter_gallery_assets version to ^0.2.0.

* Run `flutter update-packages --force-upgrade`.

* Add comment.

* Remove duplicate key.