GitLab

InvertedIndexSearch is a search backend based on inverted index
and TF-IDF ranking.

This CL implements all APIs except search, which will be in
the next cl.

Bug: 1090132
Change-Id: I3ad4507fba907ed73c3b2b49d7ddb931d0421ee8
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2262101Reviewed-by: Thanh Nguyen <thanhdng@chromium.org>
Commit-Queue: Jia Meng <jiameng@chromium.org>
Cr-Commit-Position: refs/heads/master@{#781735}