Reorganize TrackLayerDevice and move processGlyphRunForMask

The routine processGlyphRunForMask needs to move to SkGlyphRun
to use all the new positioning routines. This requires the
definition for TrackLayerDevice to be visible in SkGlyphRun.

Change-Id: I0fd20870940471cfbae29e411597e115d150893a
Reviewed-on: https://skia-review.googlesource.com/149046
Reviewed-by: Brian Salomon <bsalomon@google.com>
Commit-Queue: Herb Derby <herb@google.com>
4 files changed