static calculateRenamings(database, currVersion, newVersion) {
    currVersion = versionUtils.coerce(currVersion);
    newVersion = versionUtils.coerce(newVersion);
    const versions = Object.keys(database).sort(versionUtils.compare);
    const renamers /** !Array<!VersionRenamer> */ = [];
    for (const version of versions) {
      // Only process versions in the range (currVersion, ^newVersion].
      if (versionUtils.lte(version, currVersion)) continue;
      if (versionUtils.gt(version, newVersion)) break;

      renamers.push(new VersionRenamer(database[version]));
    }
    return renamers;
  }
Turns a database of renamings into an intermediate format that is
easier to apply.
@param {!Object} database The database of renames.
@param {string} currVersion The version to migrate from.
@param {string} newVersion The version to migrate to.
@returns {!Array<!VersionRenamer>} The collection of renamings to perform.