With this patch the window manager related functionality is split out
onto a new endpoint pair named WindowManagerServer/Client. This allows
window manager functionality to be potentially privilege separated in
the future. To this end, a new client named WMConnectionClient
is used to maintain a window manager connection. When a process
connects to the endpoint and greets the WindowServer as a window manager
(via Window::make_window_manager(int)), they're subscribed to the events
they requested via the WM event mask.
This patch also removes the hardcoding of the Taskbar WindowType to
receive WM events automatically. However, being a window manager still
requires having an active window, at the moment.
(...and ASSERT_NOT_REACHED => VERIFY_NOT_REACHED)
Since all of these checks are done in release builds as well,
let's rename them to VERIFY to prevent confusion, as everyone is
used to assertions being compiled out in release.
We can introduce a new ASSERT macro that is specifically for debug
checks, but I'm doing this wholesale conversion first since we've
accumulated thousands of these already, and it's not immediately
obvious which ones are suitable for ASSERT.
