Steps to Reproduce

1. Execute flutter run on the code sample
2. View application in light theme

Expected results:

1. TabBar icons should use a contrasting color with the appbar background so they are visible
2. When a child TabBarView is scrolled under the AppBar, the AppBar should raise its elevation and use its tint color. This works when the child is not a TabBarView

Actual results:

With Material 3 enabled on a light theme, the AppBar:

1. Defaults to a white icon on a white background
2. Does not change its elevation or tint, so it's difficult to see that something has scrolled under it.

Code sample

DartPad example here: https://dartpad.dev/?id=ce15440e9376bd9944e6a53350ff4f70

This is a modification of one of the TabBar examples from the official docs. For some reason, DartPad seems to hang/crash when attempting to scroll the first tab, but it reproduces just fine on an Android emulator.

Light mode:

Things are pretty okay in dark mode: