Use typographic font metrics when the font requests.

Use typographic font metrics when the font requests.

FreeType always returns the 'hhea' font metrics for ascent and descent,
and ignores the 'OS/2'::fsSelection::UseTypoMetrics bit. (It also
ignores the VDMX table, which makes this change correct.) This change
uses the typographic font metrics when the font requests their use.

Committed: https://skia.googlesource.com/skia/+/665b038b5745a9f5dc88b7ccfb39466a4c8750bf

[bungeman-skia, 2015-03-18 22:47:34]

bungeman@google.com changed reviewers:
+ mtklein@google.com, reed@google.com

[bungeman-skia, 2015-03-18 22:47:34]

This is currently being tried at https://codereview.chromium.org/1008933003/ to
see the effect on Blink.

This came up while creating a test font where the typographic metrics were
wildly different from the 'hhea' and 'usWin' metrics. It turns out that others
have been doing this for a long time, and if we ever get VDMX handling pulled
down here too we should try foisting it all into FreeType.

[bungeman-skia, 2015-03-19 14:47:42]

On 2015/03/18 22:47:34, bungeman1 wrote:
> This is currently being tried at https://codereview.chromium.org/1008933003/
to
> see the effect on Blink.
> 
> This came up while creating a test font where the typographic metrics were
> wildly different from the 'hhea' and 'usWin' metrics. It turns out that others
> have been doing this for a long time, and if we ever get VDMX handling pulled
> down here too we should try foisting it all into FreeType.

Interestingly, this doesn't change any Blink layout tests. I believe the reason
for this is that Blink will override with VDMX metrics, some fonts don't contain
this bit, and those that do we won't immediately see the difference very often
due to the typo metrics being often set to the same as the hhea metrics. I'd
like to go ahead with this, for some web fonts, this should improve their
spacing.

[reed1, 2015-03-19 17:08:42]

lgtm

[bungeman-skia, 2015-03-19 17:19:22]

The CQ bit was checked by bungeman@google.com

[commit-bot: I haz the power, 2015-03-19 17:19:31]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/1020643002/1

[commit-bot: I haz the power, 2015-03-19 17:44:07]

Committed patchset #1 (id:1) as
https://skia.googlesource.com/skia/+/665b038b5745a9f5dc88b7ccfb39466a4c8750bf