[ChromeRefresh] Account for potential empty avatar image

Bug: 1448950, 1427667
Change-Id: Ie51c9a42dd2197477200098bb1b1617ddadb53b2
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/4568709


Reviewed-by: Mike Wasserman <msw@chromium.org>
Code-Coverage: Findit <findit-for-me@appspot.gserviceaccount.com>
Commit-Queue: Elaine Chien <elainechien@chromium.org>
Cr-Commit-Position: refs/heads/main@{#1149420}