[omnibox chrome:omnibox] Rename OmniboxInputs to OmniboxInput

This is consistent with OmniboxOutput. We're using to input and output as
collective nouns rather than as a container for a collection of inputs and
outputs.

Bug: 891303
Change-Id: I2e7166c7e24f2bac4e84383f5b8fb4a573c9b3e2
Reviewed-on: https://chromium-review.googlesource.com/c/1387397
Commit-Queue: manuk hovanesian <manukh@chromium.org>
Reviewed-by: Orin Jaworski <orinj@chromium.org>
Reviewed-by: Tommy Li <tommycli@chromium.org>
Cr-Commit-Position: refs/heads/master@{#618969}
8 files changed