DirectWrite to not round already subpixel metrics.

DirectWrite to not round already subpixel metrics.

In keeping with the FreeType and Mac scaler contexts, do not artificially
round already subpixel metrics.

The subpixel flag should be the 'forceSubpixel' flag when it comes to
metrics. Existing backends will give subpixel metrics when 'subpixel' is
requested, but will not round proper metrics when 'subpixel' is not
requested.

Committed: https://skia.googlesource.com/skia/+/a3530ef268acbbbd84cd4c5465cdc29df5269390

[bungeman-skia, 2014-06-20 17:12:43]

This is the same as https://codereview.chromium.org/271673004/ , but at the time
I had no way to see what the change in Blink might be. I've been able to run
this by the bots now at https://codereview.chromium.org/347093002/ . So this is
saf to go into Chromium (it should result in no change).

It will mean rebaselining a number of gms, but only on the DirectWrite bots.

[reed1, 2014-06-20 17:14:24]

lgtm

[bungeman-skia, 2014-06-20 17:19:38]

The CQ bit was checked by bungeman@google.com

[commit-bot: I haz the power, 2014-06-20 17:20:26]

CQ is trying da patch. Follow status at
 https://skia-tree-status.appspot.com/cq/bungeman@google.com/344253002/1

[commit-bot: I haz the power, 2014-06-20 17:35:04]

Change committed as a3530ef268acbbbd84cd4c5465cdc29df5269390