class InputOwnership

Get information about ownership of input (replaces `DisplayOwnership`).

By default, user input is handled by the platform input pipeline

(`SceneManager`) and delivered to applications via standard UI protocols

(e.g. `fuchsia.ui.pointer.TouchSource`).

Low-level components (such as Starnix or Virtcon) that require direct access

to hardware input devices via `fuchsia.input.report.Service` must observe this

event to pause or resume reading from direct driver streams, preventing

duplicate processing or input leakage.

This protocol intentionally assumes a system-wide singleton direct-client

model where only one direct client or the platform pipeline consumes input

at any given time.

During ownership transitions (e.g. switching display ownership or view

focus), an intermediate state may occur where neither the direct client nor

the platform pipeline owns input. During any unowned or transition state, all

consumers (both direct clients and the platform pipeline) must pause reading

and processing hardware input reports until their respective ownership signal

is asserted.

Security note:

A `ViewRef` is a duplicable identity token rather than proof of view ownership,

and any caller with access to this protocol can replace the registered `ViewRef`.

Therefore, `InputOwnership` must only be routed to trusted system components.