Currently, wayland protocol headers are included with #include <foo-protocol-header.h> style in .cc files.
This requires the include paths for those headers to be added to include_dirs GN variable as public configs, so that any code which (directly or indirectly) depends on the protocol can compile.

As piman@ pointed out in crrev.com/c/1375197, this is not good in terms of build speed.
We should stop adding include paths to public configs by doing something.