In 
ProcessorEntityTracker* SharedModelTypeProcessor::CreateEntity(
    const std::string& storage_key,
    const EntityData& data)

When creating an entity, there are 2 DCHECK to check that the entity does not already exist.

The first one checks that entities_ does not contain a similar entity, the second that storage_key_to_tag_hash_ does not contain the hash.

When calling processor->remove(), the entity is removed from entities_ in SharedModelTypeProcessor::OnCommitCompleted(

but storage_key_to_tag_hash_ is never cleaned.
This means that when doing

processor()->Put(key);
processor()->Delete(key);
processor()->Put(key);

the test on storage_key_to_tag_hash_ DCHECKS.