Fix rounding for border-image-width after scaling adjustment

The scaling of the various edges/widths would always round down, which
meant that edges that were supposed to be abutting were not.

Round the scaled width instead, but take care to avoid introducing a new
overlap (which we scaled down to avoid). Use LayoutUnits for this since
we probably want to just compute the widths to LayoutUnit directly in
the future for slightly improved fidelity (TODO added).

Also, fix typo in |include_rigt_edge|.

Bug: 918994
Change-Id: I359fd54d30ddcfa235217e14f340cd6139e9d040
Commit-Queue: Fredrik Söderquist <>
Reviewed-by: Stephen Chenney <>
Cr-Commit-Position: refs/heads/master@{#629133}
12 files changed