leanback: fix bad state of mFocusPosition

When smoothScroller starts, the target position is cropped by adapter
size, leanback doesn't adjust its internal mFocusPosition, which
causes unable to focus to a child in onRequestFocusInDescendants().

The launcher could fix this by double check the position before pass
to setSelectionSmooth().

Bug: 32118060
Test: testSmoothScrollerOutRange
Change-Id: I5c4ea3b3b4776971f511b0d689e4f9c66bb5ae47
2 files changed