Improve name table handling.

Robust reading of name tables.

Internally use sk_sp with LocalizedStrings. After landing, update the
public api as well.

Replace High/Low with Leading/Trailing surrogates in naming. This naming
is far easier to get right.

Change-Id: I542934ea8189ced1c2cbdd1539f9ebba562f0731
Reviewed-on: https://skia-review.googlesource.com/148123
Reviewed-by: Herb Derby <herb@google.com>
Commit-Queue: Ben Wagner <bungeman@google.com>
11 files changed