repoview: bypass changelog method to computed cache key Getting the data necessary for the cache key using the changelog/revlog method adds a significant overhead. Given how simple the underlying implementation is and often this code is ran, it makes sense to violate layering and directly compute the data. Testing `hg log` on Mozilla-central, this reduce the time spent on changelog cache validation by an extra half: before: 12.2s of 69s after: 6.1s of 62s Total speed up from this patch and it's parent is 3x (With stupid python profiler overhead) The global speedup without profiler overhead is still there, Before: 51s After: 39s (-23%)