AccessibilityNodeInfo for visible views should reported.

1. AccessibilityNodeInfos for visible views should always
   be reported and the clients should be able to check
   whether that node info is shown to the user. For example,
   focus search may return a node that is not on the screen
   and the accessibility layer may decide to give it focus
   which scroll the source view in the screen.

bug:6421991

Change-Id: Idc1fd8512dda767abe802aacedb0c69582e6fc2a