New setters extracting values from complex unit dimensions.

These new setters allow defining configuration dependent values at
runtime (to some extend) in a way that is currently not possible.

See go/widgets-configuration-setters for details

Bug: 178591376
Test: atest android.widget.cts.RemoteViewsTest
Change-Id: I5a1582b4fa7f70ad8d922c72f773fe254ef2f9ff