Move FontConfig factory into separate file.

Move FontConfig factory into separate file.

This moves the SkFontMgr::Factory implementation which creates a
FontMgr around FontConfig into its own file, and allows the user
to create one manually.

Committed: https://skia.googlesource.com/skia/+/0b1de2626a289ab21bd3b93277ed34d022824b3d

[bungeman-skia, 2015-06-16 20:55:24]

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

[bungeman-skia, 2015-06-16 20:55:25]

I think this is the last of this sort of cleanup which can be made without also
updating Chromium. Further changes will need more coordination.

[bungeman-skia, 2015-06-16 21:32:47]

The CQ bit was checked by bungeman@google.com to run a CQ dry run

[commit-bot: I haz the power, 2015-06-16 21:33:15]

Dry run: CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/1189753007/1

[commit-bot: I haz the power, 2015-06-16 21:34:38]

The CQ bit was unchecked by commit-bot@chromium.org

[commit-bot: I haz the power, 2015-06-16 21:34:39]

Dry run: Try jobs failed on following builders:
  Build-Ubuntu-GCC-Arm7-Debug-Android-Trybot on client.skia.compile (JOB_FAILED,
http://build.chromium.org/p/client.skia.compile/builders/Build-Ubuntu-GCC-Arm...)

[bungeman-skia, 2015-06-16 21:43:02]

The CQ bit was checked by bungeman@google.com to run a CQ dry run

[commit-bot: I haz the power, 2015-06-16 21:43:23]

Dry run: CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/1189753007/20001

[commit-bot: I haz the power, 2015-06-16 21:48:33]

The CQ bit was unchecked by commit-bot@chromium.org

[commit-bot: I haz the power, 2015-06-16 21:48:34]

Dry run: This issue passed the CQ dry run.

[reed1, 2015-06-17 14:52:29]

header looks very clear.
lgtm

[bungeman-skia, 2015-06-17 14:55:14]

The CQ bit was checked by bungeman@google.com

[commit-bot: I haz the power, 2015-06-17 14:55:28]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/1189753007/20001

[commit-bot: I haz the power, 2015-06-17 14:56:02]

Committed patchset #2 (id:20001) as
https://skia.googlesource.com/skia/+/0b1de2626a289ab21bd3b93277ed34d022824b3d