fix a bug imported in "fix a typo omni.clientWidth is too small"
fix a bug imported in "fix a typo omni.clientWidth is too small"

0.8 factor is necessary, but not a typo,
and now front/vomnibar should compute it, and pass iframe width to backend

This reverts commit b361b12f6d7b36d8b742c7db7dc1ab85815c7fca.

gdh1995/vimium-plus,gdh1995/vimium-plus,gdh1995/vimium-plus