[omnibox] Experimental feature to group suggestions by type

This implements an experimental feature (behind a flag) to group
Omnibox suggestions by type, search results first, followed by other
types, after the default match, which does not move.

Bug: 966462
Change-Id: I6870652be8f733b185ad1dcca946fb3091db0b09
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1625811
Reviewed-by: Justin Donnelly <jdonnelly@chromium.org>
Commit-Queue: Kevin Bailey <krb@chromium.org>
Cr-Commit-Position: refs/heads/master@{#662749}
7 files changed