upload_symbols: add some basic upload stats

Log the number of symbols we uploaded and how long the overall process
took.  This is useful when triaging and gathering data after the fact.

This also renames the developer-only --upload-count to --upload-limit
so that the names stay consistent.  I'm probably the only one who uses
this flag, so it won't impact people.

BUG=chromium:209442
TEST=`./buildbot/run_tests` passes
TEST=`upload_symbols foo.sym` final log line looks good

Change-Id: I48133b2a295233b8dcacf02c48ffa3cb2f82a2b7
Reviewed-on: https://chromium-review.googlesource.com/185623
Tested-by: Mike Frysinger <vapier@chromium.org>
Reviewed-by: Yu-Ju Hong <yjhong@chromium.org>
Commit-Queue: Mike Frysinger <vapier@chromium.org>
2 files changed