(DO NOT LAND) Use roundOut() rather than round() to round glyph bounds in simple path

Use roundOut() rather than round() to round glyph bounds in simple path

This patch changes round() to roundOut() to round glyph bounds to avoid
possible rendering outside of the visual overflow rect.

It was pointed out in a review comment[1] by jbroman, confirmed by this
patch fixed fast/block/lineboxcontain/glyphs-clipping.html.

Complex path has the same fix in the CL[1].

[1] https://codereview.chromium.org/1316843005/#msg5

BUG=452914

[kojii, 2015-09-01 17:40:05]

kojii@chromium.org changed reviewers:
+ eae@chromium.org, jbroman@chromium.org

[kojii, 2015-09-01 17:46:58]

eae@, jbroman@, WDYT?

The roundOut for simple path changes a good number of results only on Linux,
see:
https://storage.googleapis.com/chromium-layout-test-archives/linux_chromium_r...
By quickly looking through, mostly one pixel diff, but sometimes it affects box
sizing, and sometimes paint invalidation rects are changed.

I can rebaseline all these for Linux (after checking more carefully) but your
thoughts on whether we should take this fix or not is appreciated.

[eae, 2015-09-01 17:55:01]

Not sure it's worth it, how long do we expect to keep the simple path for?

[kojii, 2015-09-02 01:10:53]

On 2015/09/01 17:55:01, eae wrote:
> Not sure it's worth it, how long do we expect to keep the simple path for?

A few month, hopefully ;) ?

Agreed not to take this CL, unless anyone else have other opinions.

[eae, 2015-09-02 01:13:16]

Agreed.

I'm not opposed to it but doubt it's worth the effort. If someone feels strongly
about it and is willing to do the work to update the test results then by all
means, go for it.