* Add it to CE HTML, for compatibility with site styles.
* Add it to DM HTML of newly created references only. Existing
references just use whatever classes we got from Parsoid, to avoid
unnecessary DOM changes and dirty diffs.
Bug: T265930
Depends-On: I61a2132f3876e2d9567d985358f51eb51c479813
Change-Id: I9d6856f03071c09617b8ae7db938135a3e30fe8e