Update {virtual,override,final} for base to follow C++11 style.

This patch was automatically generated using a variation of
https://codereview.chromium.org/598073004

BUG=417463

Review URL: https://codereview.chromium.org/842993002

Cr-Commit-Position: refs/heads/master@{#310660}
2 files changed