When a file is added in one commit and then edited in another, we were incorrectly showing that file as edited when viewing commit ranges. The problem here was that we weren't propagating the new-file state through when the ancestor list included adding the file. Testing Done: - Ran unit tests. Newly-added test failed before the fix and succeeds after. - Posted a change that involved a bunch of commits where some files were added in one commit and then changed in later ones. Saw that commit range diffs properly showed the file as added when the selected base commit was the commit which added the file or earlier.