remove unused serialization in textblob

The SKTextBlob serialization code that is tested by Skia is
unused by Chrome. The serialization code that is
used by Chrome is untested by Skia.

Remove the unused code; test the used code.

The code path introduced nearly a year ago,
likely for slimming paint, attempts to make
text blobs smarter by allowing the reuse of typefaces.

Maybe there needs to be a Chrome bug / feature
request to use this?

If if turns out there is no interest to do so,
This CL aligns used interfaces with tests.

R=reed@google.com,fmalita@google.com,bungeman@google.com

Bug: skia:6818
Change-Id: I9b3ec0c326495322986ba26f20f901bcb208be73
Reviewed-on: https://skia-review.googlesource.com/141542
Reviewed-by: Cary Clark <caryclark@skia.org>
Reviewed-by: Florin Malita <fmalita@chromium.org>
Reviewed-by: Ben Wagner <bungeman@google.com>
Reviewed-by: Mike Reed <reed@google.com>
Commit-Queue: Cary Clark <caryclark@skia.org>
Auto-Submit: Cary Clark <caryclark@skia.org>
3 files changed