A few more small changes to make GrAtlasTextBlob nearly self contained

A few more small changes to make GrAtlasTextBlob nearly self contained

Note: There is still a bit of friendliness, but its going to require
some creativity to deal with.

BUG=skia:
GOLD_TRYBOT_URL= https://gold.skia.org/search2?unt=true&query=source_type%3Dgm&master=false&issue=1606943002

Committed: https://skia.googlesource.com/skia/+/323c2ebe9e171d399c922f1efb5b6a2ca9d56b2e

[joshua.litt, 2016-01-19 16:02:45]

Description was changed from

==========
A few more small changes to make GrAtlasTextBlob nearly self contained

Note: There is still a bit of friendliness, but its going to require
some creativity to deal with.

BUG=skia:
==========

to

==========
A few more small changes to make GrAtlasTextBlob nearly self contained

Note: There is still a bit of friendliness, but its going to require
some creativity to deal with.

BUG=skia:
GOLD_TRYBOT_URL=
https://gold.skia.org/search2?unt=true&query=source_type%3Dgm&master=false&is...
==========

[joshualitt, 2016-01-19 16:06:18]

joshualitt@google.com changed reviewers:
+ bsalomon@google.com, joshualitt@google.com, jvanverth@google.com

[joshualitt, 2016-01-19 16:06:19]

This CL hides GrAtlasTextBlob's internals from GrAtlasTextContext and
GrTextUtils.  GrAtlasTextBatch and GrTextBlobCache have been made friends.  I
don't think we can really get rid of GrTextBlobCache's friendship, but we might
be able to do something about GrAtlasTextBatch.  In any case, for the time being
this will probably be all the cleanup I'm doing in this area.  The follow on
will address the bounds issue.

[bsalomon, 2016-01-19 17:08:08]

rubber stamp lgtm

[joshualitt, 2016-01-20 14:37:18]

The CQ bit was checked by joshualitt@google.com

[commit-bot: I haz the power, 2016-01-20 14:37:23]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/1606943002/20001
View timeline at
 https://chromium-cq-status.appspot.com/patch-timeline/1606943002/20001

[commit-bot: I haz the power, 2016-01-20 14:48:54]

Description was changed from

==========
A few more small changes to make GrAtlasTextBlob nearly self contained

Note: There is still a bit of friendliness, but its going to require
some creativity to deal with.

BUG=skia:
GOLD_TRYBOT_URL=
https://gold.skia.org/search2?unt=true&query=source_type%3Dgm&master=false&is...
==========

to

==========
A few more small changes to make GrAtlasTextBlob nearly self contained

Note: There is still a bit of friendliness, but its going to require
some creativity to deal with.

BUG=skia:
GOLD_TRYBOT_URL=
https://gold.skia.org/search2?unt=true&query=source_type%3Dgm&master=false&is...

Committed:
https://skia.googlesource.com/skia/+/323c2ebe9e171d399c922f1efb5b6a2ca9d56b2e
==========

[commit-bot: I haz the power, 2016-01-20 14:48:55]

Committed patchset #2 (id:20001) as
https://skia.googlesource.com/skia/+/323c2ebe9e171d399c922f1efb5b6a2ca9d56b2e