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This is part of EG1 to EG2 migration, which involves moving
EarlGrey code from app-side helpers into test code.
EarlGrey2 has multiprocess architecture,
where Chrome Test and Chrome App are separate processes

Change-Id: Ib41116bb8df8c8383ad8a76460d5643560983716
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1732157
Commit-Queue: Maksym Onufriienko <monufriienko@chromium.org>
Reviewed-by: Eugene But <eugenebut@chromium.org>
Cr-Commit-Position: refs/heads/master@{#683767}