src/vs/editor/browser/widget/diffEditorWidget.ts/DiffEditorWidget/_getClassName
class DiffEditorWidget:	private static _getClassName(theme: IColorTheme, renderSideBySide: boolean): string {
		let result = 'monaco-diff-editor monaco-editor-background ';
		if (renderSideBySide) {
			result += 'side-by-side ';
		}
		result += getThemeTypeSelector(theme.type);
		return result;
	}