Simplify the high efficiency chip unittest

This is needed to better unit test the dialog that I'm adding in a
subsequent CL.

Bug: 1356638
Change-Id: Ibacd742410753ca40d1740464ecb2e1958e1cbf3
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/3882483


Reviewed-by: Taylor Bergquist <tbergquist@chromium.org>
Commit-Queue: Alison Gale <agale@chromium.org>
Cr-Commit-Position: refs/heads/main@{#1044775}