A lot of the steps involved in creating a VkImage, allocating backing
memory, and binding the VkImage to the memory do not rely specifically
on Wayland features and could be common to other WSI backends.
This commit attempts to decouple the create_and_bind_swapchain_image()
function in the wsi/wayland/swapchain.cpp from Wayland and wsialloc
specific parts, and instead move the independent parts related to
external memory management to a new external_memory class. This will
allow the independent code to be re-used in future WSI backends.
Signed-off-by: Dennis Tsiang <dennis.tsiang@arm.com>
Change-Id: I8c13ccbbfaef0d345fcd06192e6de484dd53645f
