Use Previous/NextSibling instead of Slow*Child().

The former methods should be faster.

Change-Id: I1fb5ae5eeaea78b561cffbe6a78594af0f7a75b6
Reviewed-on: https://chromium-review.googlesource.com/655078
Reviewed-by: Morten Stenshorne <mstensho@opera.com>
Commit-Queue: Rune Lillesveen <rune@opera.com>
Cr-Commit-Position: refs/heads/master@{#500402}
1 file changed