Currently, the DiffViewHeader hook's second and third parameters are Revision objects (or null). These can be replaced with RevisionRecord objects. However, those RevisionRecord objects correspond to the return values of the DifferenceEngine's (first hook parameter) getOldRevision and getNewRevision, so really the replacement only needs to pass a DifferenceEngine
New name: DifferenceEngineViewHeader (to match DifferenceEngineOldHeaderNoOldRev)
Deployed extensions to update:
- FlaggedRevs https://gerrit.wikimedia.org/r/607386
- MobileFrontend https://gerrit.wikimedia.org/r/607387
- RevisionSlider https://gerrit.wikimedia.org/r/607393
- Thanks https://gerrit.wikimedia.org/r/607388
- VisualEditor https://gerrit.wikimedia.org/r/607390