Slim Skia down to just one murmur3 implementation.

BUG=skia:

Committed: https://skia.googlesource.com/skia/+/6ac0037b70410ff7d5ce5788bc89314223e1a587

Committed: https://skia.googlesource.com/skia/+/67a3271f0de9ccc32d559b042b862528272047cc

R=reed@google.com, mtklein@google.com

Author: mtklein@chromium.org

Review URL: https://codereview.chromium.org/376183004
3 files changed