src/vs/workbench/contrib/scm/browser/dirtydiffDecorator.ts/getChangeTypeColor
function getChangeTypeColor(theme: IColorTheme, changeType: ChangeType): Color | undefined {
	switch (changeType) {
		case ChangeType.Modify: return theme.getColor(editorGutterModifiedBackground);
		case ChangeType.Add: return theme.getColor(editorGutterAddedBackground);
		case ChangeType.Delete: return theme.getColor(editorGutterDeletedBackground);
	}
}