Restrict when a dragged item's target index is incremented or decremented.
Restrict when a dragged item's target index is incremented or decremented.

The [moveTargetIndex] should only be incremented or decremented when the element being dragged over has shifted due to a previous drag (without a drop).

PiperOrigin-RevId: 193207043

angulardart/angular_components,angulardart/angular_components,angulardart/angular_components