Remove unique glyph IDs from glyph runs

The unique calculation is to costly to do for SkTextBlobs every
time because there may be a cache hit in the GrTextBlob cache.
In the future I will move the unique ID calculation to the GrTextBlob
creation.

Change-Id: I7e10e8f22a3bc729fab12b2cf7e9732441be7f31
Reviewed-on: https://skia-review.googlesource.com/c/164623
Reviewed-by: Mike Klein <mtklein@google.com>
Commit-Queue: Herb Derby <herb@google.com>
8 files changed