This service allows linking the EditFilterMergedContent and
PageSaveComplete hooks for the same edit, so we can update rev IDs in
the abuse_filter_log table. Having such a services also avoids two hacky
static props, and should allow separating the hook handlers easily.
Change-Id: I622d15225ee3af202cb5730a7112652aef8ca71a
This makes VariableHolder a true value object, and introduces a
stateless service, VariableManager, to operate on it.
Note, in theory, this new service is still cyclically coupled with
LazyVariableComputed. However, it's now two stateless service being
coupled, not two smart/god value objects, so we've still earned
something. For now, the dependency is hidden by using a callback. Some
alternatives for that are mentioned in a code comment.
Bug: T261069
Change-Id: I2f2c84c8e91472ba36084a8bbb4a923f6e04354b
