https://github.com/flutter/flutter/issues/61736

* Make scrollbar thickness and radius customizable

https://github.com/flutter/flutter/issues/29576
https://github.com/flutter/flutter/issues/36412

* Add docs for constants

* No more magic numbers in test

SceneBuilder.addPicture() is implemented in C++, and if `picture`
is null, it will seg-fault. This catches the problem before that
happens.

This updates the default value of the `invertMeaningOfVerticalAndHorizontal`
argument from true to false.

https://github.com/flutter/flutter/issues/61470

https://github.com/flutter/flutter/issues/60559

This reverts commit b7b60a2d.

Revert "Reland "Add support for Dart Development Service (DDS) in Flutter Tools (#61276)" (#61633)" (#61641)

This reverts commit 594c3541.

This reverts commit a1a5a8f6.

Add feature flags for android, ios, and fuchsia (on by default). After updating the g3 rollers, the fuchsia feature will be turned off by default. Creates a simpler base type of feature flags for g3 to extend.

Updates android, ios, fuchsia workflows to use feature flags check.
Removes concept of stable artifacts and checks on flutter version.

Fixes #58999
#52859
#12768

complete removal of all generate functionality

Fixes #61508

`showDialog()` and `showGeneralDialog()` were allowing transparent
colors but then triggering an assertion down the stack while building
the modal barrier. The assertion existed to keep from animating from
transparent to transparent, but there's no need for the assertion,
since we can just treat the transparent case as the same as the null
case -- no animation necessary.

This was testing that concurrent reloads were rejected. This is now allowed (as of #55376 (which has non-devicelab integration + unit tests).

Remove git dependencies from pub-cache

#61487

* Promtoe WidgetTester.ensureVisible

* modify according to tvolkert@