Instead of reparenting the content, use input-only windows to
set cursors and capture clicks on the window frame. This avoids
some of the problems that were introduced by content_window, such
as black flashes and non-working opacity.
Don't mention "auto mnemonics", since those methods are purely about
scheduling a delayed display, and that makes understanding the code a
bit harder.
https://bugzilla.gnome.org/show_bug.cgi?id=697144
Update the documentation and users of this function to handle
the future case that that we have some internal decorations to the window and
useable allocation is thus smaller.
By having a separate out parameter there is no need to have an in/out function
and allows for greater robustness.
The current implementation simply returns the allocation provided.
Showing mnemonics immediately on modifier press can be annoying and
distracting when the user is just trying to Alt+Tab into another
application/window since the mnemonic will show up and quickly vanish
again when we receive the focus out event.
https://bugzilla.gnome.org/show_bug.cgi?id=672431
In the process of removing all sealed members from headers.
At the same time, add a gtkwindowprivate.h header and move
all internal functions from gtkwindow.h there.
