[Search ranking] Clean up ranking_item_util.

We have a lot of dead code behind unused feature flags from past
experiments in the search ranking codebase, so I'm going to do some
clean up CLs.

This one removes the utility code for expanding omnibox result
subtypes, used for the original cat model.

Bug: 1028447
Change-Id: I2f88c68e08505edbc559b7bae63310c2b850c8a8
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1935629
Reviewed-by: Thanh Nguyen <thanhdng@chromium.org>
Commit-Queue: Tony Yeoman <tby@chromium.org>
Cr-Commit-Position: refs/heads/master@{#719486}
2 files changed