Add @embed directive for resize-nw-se and resize-nw-sw icons

Follows-up 0d7ee1a74a7ad9fbf4c.

These were making 2 extra http requests when first clicking a
resizable image on a page.

Change-Id: I9a16a23853899800238294975fb481cafcfe4001
Merge "Add @embed directive for resize-nw-se and resize-nw-sw icons"