At the moment, dmabuf importing is scattered all over the place in kwin.
It would be great if we had one function that takes dma-buf attributes
and returns an EGLImage if successful.
As the first step, make linux-dmabuf-v1 implementation provide dmabuf
attrs compatible with KWin::DmaBufAttributes.
This makes KWin switch to in-tree copy of KWaylandServer codebase.
KWaylandServer namespace has been left as is. It will be addressed later
by renaming classes in order to fit in the KWin namespace.
dmabuf-feedback allows the compositor to give the client feedback on what
formats and modifiers are best to use, and for which devices it needs to
allocate its buffers, which improves performance and efficiency.
Currently, the BufferInterface encapsulates all the kinds of client
buffers. This has become a somewhat annoying issue as we want to
reference the shm pool if a shm buffer is destroyed, or have custom
buffer readiness logic for linux dma-buf client buffers.
Implementing all of that with the current abstractions will be
challenging as there's no good separation between different client
buffer types.
This change splits the BufferInterface class in three sub-classes -
DrmClientBuffer, LinuxDmaBufV1ClientBuffer, and ShmClientBuffer.
In addition to that, this change fixes the broken buffer ref'ing api.
