See: https://codesearch.wmcloud.org/search/?q=VirtualRESTService (for non-WMF deployed repos).
NOTE: In the search above, VisualEditor and ContentTranslation are being migrated slowly. They're special cases because we need to make use of cache warming for parsoid outputs.
Acceptance Criteria
- Replace for MathSearch - https://gerrit.wikimedia.org/r/930853
NOTE: Once we have replaced usage in these extensions, we can hard deprecate the class and remove in future versions of MW.