after previous change, which moved icons to .png format and
to subdirectory img/.

Bug: v8:7327
Notry: true
Change-Id: Iebbbe175cc65ed1f2e505084344a2b55864732e7
Reviewed-on: https://chromium-review.googlesource.com/c/1494009
Commit-Queue: Sigurd Schneider <sigurds@chromium.org>
Reviewed-by: Georg Neis <neis@chromium.org>
Cr-Commit-Position: refs/heads/master@{#59940}