Add FakeOmnibox() EG matcher to improve code formatting.

Bug: None
Change-Id: I52f38fe4a1699c9eebd0439f3b8ac9252e855956
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1574293
Auto-Submit: Eugene But <eugenebut@chromium.org>
Reviewed-by: Justin Cohen <justincohen@chromium.org>
Commit-Queue: Eugene But <eugenebut@chromium.org>
Cr-Commit-Position: refs/heads/master@{#654226}
10 files changed