Roll AFDO from 78.0.3877.0_rc-r1-merged to 78.0.3878.0_rc-r1-merged

This CL may cause a small binary size increase, roughly proportional
to how long it's been since our last AFDO profile roll. For larger
increases (around or exceeding 100KB), please file a bug against
gbiv@chromium.org. Additional context: https://crbug.com/805539

Please note that, despite rolling to chrome/android, this profile is
used for both Linux and Android.

The AutoRoll server is located here: https://autoroll.skia.org/r/afdo-chromium-autoroll

Documentation for the AutoRoller is here:
https://skia.googlesource.com/buildbot/+/master/autoroll/README.md

If the roll is causing failures, please contact the current sheriff, who should
be CC'd on the roll, and stop the roller if necessary.

TBR=gbiv@chromium.org

Change-Id: I77390e1e5abdaa14ffb5bf2a7f77bef03ab4fdf5
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1746193Reviewed-by: chromium-autoroll <chromium-autoroll@skia-public.iam.gserviceaccount.com>
Commit-Queue: chromium-autoroll <chromium-autoroll@skia-public.iam.gserviceaccount.com>
Cr-Commit-Position: refs/heads/master@{#685491}

chrome/android/profiles/newest.txt

-chromeos-chrome-amd64-78.0.3877.0_rc-r1-merged.afdo.bz2
\ No newline at end of file
+chromeos-chrome-amd64-78.0.3878.0_rc-r1-merged.afdo.bz2
\ No newline at end of file