[INTERNAL] add IResourceVisitor

Change-Id: Ic319d27a89e520bd7c9d269730e733266adfe75f
Reviewed-on: http://saros-build.imp.fu-berlin.de/gerrit/1689
Tested-by: Jenkins CI
Reviewed-by: Holger Schmeisky <google@schmeisky.com>
Reviewed-by: Arndt Lasarzik <alasarzik@gmail.com>
Reviewed-by: Franz Zieris <zieris@inf.fu-berlin.de>