Added PRIVATE_FLAG_LAYOUT_CHILD_WINDOW_IN_PARENT_FRAME window flag

Allows us to differentiate between child windows that always want to be
laid-out in the parent frame regardless of multi-windowing mode
(PopupWindows) and those that don't (SurfaceViews).

Bug: 26255254
Change-Id: Icbc245a24f9a38698444196846ddb25016ef7e2a
3 files changed