Merge third_party/smhasher/src from https://chromium.googlesource.com/external/smhasher.git at b52816cce35fbfdda7d56c533cf53d15201513e3

This commit was generated by merge_from_chromium.py.

Change-Id: Iea5dd2cd1c9d78ae0583e4005d7d242c9b63dfe0