Avoid running layout transitions on unattached views and windows

LayoutTransition causes artifacts in some situations where a window is just
becoming visible or a container is just being added to the view tree when animations
are kicked off in LayoutTransition due to the normal automatic mechanism of running
animations when views are added/removed/etc. The problem is that containers in these
situations may have children with positions and sizes of (0, 0), causing the animation to
animate from this default/nonsense value to whatever is appropriate for the views when
they are first laid out and drawn. The end result is correct, but the animation is
superfluous and silly.

The fix is to avoid running any kind of transition animation on windows that are not
currently visible or containers that are not currently atached to the view hierarchy.
This should avoid the situation by only allowing the animations to run after the containers
and windows are visible and set up correctly.

Issue #6544410 issue with layout transition when first showing the activity

Change-Id: I737b2598887ef806dec3b02a483a8e8ff2c3d4e2