Allows Accessibility to focus on specified view in AbstractFloatingView.

Here, the first item in an ArrowPopup or Folder are focused on.

Note: There's another pre-existing bug where it announces
"Home screen x of y" when the floating view appears; this
change doesn't address that.

Fixes: 147470419
Change-Id: I1dc70edc21ea7c19a5742208512738d6c4a94067