Update fontMgr to take list of bcp47 language tags.

Update fontMgr to take list of bcp47 language tags.

This will enable clients to pass more than one bcp47 tag to ensure
that the most appropriate font is selected.

BUG=chromium:422180
Committed: https://skia.googlesource.com/skia/+/c20386e3937d3d398ac9b35f9c7d997e972ade98

[bungeman-skia, 2014-10-22 23:08:58]

bungeman@google.com changed reviewers:
+ djsollen@google.com, tomhudson@google.com

[bungeman-skia, 2014-10-22 23:08:59]

The idea is to have the behavior change behind a flag, then on the Blink side
make the change for Android and add the flag in blink_skia_config.gyp at the
same time. We can then just cherry-pick these two changes as-is. After that we
can remove the old code from Skia and then remove the flag from Blink.

[djsollen, 2014-10-23 12:30:45]

lgtm

[bungeman-skia, 2014-10-23 13:57:05]

The CQ bit was checked by bungeman@google.com

[commit-bot: I haz the power, 2014-10-23 13:58:03]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/670243002/1

[commit-bot: I haz the power, 2014-10-23 14:08:10]

Committed patchset #1 (id:1) as c20386e3937d3d398ac9b35f9c7d997e972ade98