rails/rails — pull request #5312 by kennyj (2012-03-07 04:11:53+00:00)
Title: [3-1-stable] Use 1.9 native XML escaping to speed up html_escape and shush regexp warnings

This PR is cherry-picking 63cd9432265a32d222353b535d60333c2a6a5125 to backport to 3-1-stable .
This is @jeremy's commit :)

Since it seems that there is a demand, I send PR.
If we preferred stability, please close it.
Please see https://github.com/rails/rails/issues/3927 (last comments)