[Omnibox] Classify document provider results.

This CL styles the parts of document results’ descriptions which match the
user input. E.g., given the user input 'rain if you dare', and a document
titled 'how to tell if your kitten is a rainbow', the result should display
"if", "you" in "your", and "rain" in "rainbow" as bolded:

how to tell if your kitten is a rainbow
            ^^ ^^^              ^^^^

Bug: 925483
Change-Id: I4c0f255ae5bbefa57e9980ade626efac69a76a18
Reviewed-on: https://chromium-review.googlesource.com/c/1435983
Commit-Queue: manuk hovanesian <manukh@chromium.org>
Reviewed-by: Justin Donnelly <jdonnelly@chromium.org>
Cr-Original-Commit-Position: refs/heads/master@{#626773}(cherry picked from commit 7c3b9739973bb7bda4715a3496530b13695b4aec)
Reviewed-on: https://chromium-review.googlesource.com/c/1450469
Reviewed-by: manuk hovanesian <manukh@chromium.org>
Cr-Commit-Position: refs/branch-heads/3683@{#134}
Cr-Branched-From: e51029943e0a38dd794b73caaf6373d5496ae783-refs/heads/master@{#625896}
4 files changed