Sending A11y events when a view becomes invisible.

Making the A11y event sending to A11y services when a view becomes
invisible if the ancestors of this view are all visible, and this view
becomes invisible from visible.

Bug: 130273130
Test: a11y CTS & unit tests
Change-Id: I836d3e34c7a9cba31843d34922b7ba02a8a062f0