Run dev/bots/test's flutter drive test in preview-dart-2 (flutter#15090)

* Run dev/bots/test's flutter drive test in preview-dart-2

* Fix extension callback type

* More type fixes

Allow changing a clipper's type (ShapeBorderClipper,_BottomAppBarClip…

…per). (flutter#14937)

The downcast was crashing when toggling hasNotch for BottomAppBar.

Move quotes around to help Powershell 2.0 to substitute variable with…

… value (flutter#14907)

Add a hasNotch flag to BottomAppBar (flutter#14856)

Update TabBar indicator painter when tab controller changes (flutter#…

…14825)

Update some http links to https (flutter#14762)

These URLs all automatically redirect HTTP to HTTPS so makes sense to point users at the secure versions.

Roll engine to e5b72e5 (flutter#14759)

flutter#14751

Re-apply "Send nextId in addition to previousId for traversal order" (f…

…lutter#14694)

Re-apply "Send nextId in addition to previousId for traversal order (flutter#14676)"

ScaffoldGeometry plumbing. (flutter#14580)

Adds a ScaffoldGeometry class and ValueNotifier for it.
A scaffold's ScaffoldGeometry notifier is held in the _ScaffoldState, and is passed to _ScaffoldScope.
New ScaffoldGemometry objects are built and published to the notifier.

Add annotations to ignore analyzer errors on pre-dev.22 SDKs (flutter…

…#14599)