Framework changes for go/widget-size-specification

Update the framework to:

1 - Allow creating RemoteViews with a mapping from size to layouts
2 - Use the closes sized layout in any given situation
3 - Allow the launher to specify the current size when inflating a
    remote views

Bug: 179025145
Test: atest android.widget.cts.RemoteViewsSizeMapTest
Change-Id: Icf98d01bd0cf8b48c47555a1af6acb498b46b1a4