Add padding to numeric labels for stacked bar plotter.
Add padding to numeric labels for stacked bar plotter.

Bug: chromium:866423
Change-Id: I7d0ca48894cb7414d70493cfffa25fa743353ecd
Reviewed-on: https://chromium-review.googlesource.com/1216682
Reviewed-by: Mythri Alle <8217f39113e9154bc3569f26a6f1ff5840cea8d8@chromium.org>
Commit-Queue: Anthony Alridge <a645992b9bc8e5e2c65dfde706a199cd04747be0@google.com>

catapult-project/catapult,catapult-project/catapult,catapult-project/catapult,catapult-project/catapult,catapult-project/catapult,catapult-project/catapult,catapult-project/catapult