Standardize usage of virtual/override/final in base/

BUG=417463
TBR=danakj@chromium.org

Review URL: https://codereview.chromium.org/668783004

Cr-Commit-Position: refs/heads/master@{#300447}


CrOS-Libchrome-Original-Commit: 5648818ef9d5ef5fda79cd5dde2e42567af07785
119 files changed
tree: 435bf3d8d0433e894fb732b40b39f8f6e9623f08
  1. base/
  2. build/
  3. components/
  4. dbus/
  5. device/
  6. ipc/
  7. mojo/
  8. testing/
  9. third_party/
  10. ui/