Refactor BinaryUploadService::Result -> string code

Change-Id: I3f47dadec2c1619ed4b4a3131c52fe1a6bef7d5b
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2068053
Commit-Queue: Dominique Fauteux-Chapleau <domfc@chromium.org>
Reviewed-by: Daniel Rubery <drubery@chromium.org>
Cr-Commit-Position: refs/heads/master@{#744269}
3 files changed