Reduce redundancy in `power_mobile` benchmark by reusing code from

`PerfBenchmarkWithProfiling`.

Change-Id: I3ca081af21c4bb593d5e83ed26d599a686beb00d
Bug: chromium:1338581
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/3865954


Commit-Queue: Tushar Agarwal <agarwaltushar@google.com>
Reviewed-by: Mikhail Khokhlov <khokhlov@google.com>
Cr-Commit-Position: refs/heads/main@{#1040972}