Chromium coding standard
(https://chromium.googlesource.com/chromium/src/+/master/styleguide/c++/c++.md#Multiple-inheritance)

In this case, a structure associating the 2 values is sufficient.

BUG=

Review-Url: https://codereview.chromium.org/2651903002
Cr-Commit-Position: refs/heads/master@{#42618}