[Courgette] Store delta encoding as signed int32.
Owing to AdjustmentMethod permuting Rel32Address items, difference of
successive items may be negative. Previously Courgette stores deltas
vectors using uint32, so negative values can take 5 bytes each.
This CL changes storage of deltas vectors to signed int32. Experiment
(goo.gl/vvVADx) shows total diff file reduction of ~3%, and zipped
diff file reduction of ~1.5%.
We apply the same change for Abs32Address items for consistency.
Review URL: https://codereview.chromium.org/1328703002
Cr-Commit-Position: refs/heads/master@{#348039}
4 files changed
