Minor refactor.
Split 'common/' into commit '6765948d05e8aeaa5d7ab19c7ca30f422d1675fa'

git-subtree-dir: common
git-subtree-mainline: 5fbfabe44b56fc9eff31649f0cef2771de6d2ea9
git-subtree-split: 6765948d05e8aeaa5d7ab19c7ca30f422d1675fa