6cae753a4c
We want to allow projects to define their own labels, so we can't assume the label list is global. In typical cases, we can access it through a ProjectControl, ChangeControl, or related factory. This does result in a few more places where we propagate NoSuchProject/ChangeExceptions where there were none before. This is intended: operations that query/modify labels on, say, a bare Change.Id now do need to verify that the project/change exists. For now, leave code in LabelTypesProvider, but try not to inject LabelTypes where at all possible. Change-Id: I4936ccafdb41848aaac3e335adf4648369d6abbc