src/vs/workbench/contrib/scm/browser/dirtydiffDecorator.ts/getChangeType
function getChangeType(change: IChange): ChangeType {
	if (change.originalEndLineNumber === 0) {
		return ChangeType.Add;
	} else if (change.modifiedEndLineNumber === 0) {
		return ChangeType.Delete;
	} else {
		return ChangeType.Modify;
	}
}