src/vs/editor/contrib/folding/browser/foldingDecorations.ts/FoldingDecorationProvider/deltaDecorations
class FoldingDecorationProvider:	deltaDecorations(oldDecorations: string[], newDecorations: IModelDeltaDecoration[]): string[] {
		return this.editor.deltaDecorations(oldDecorations, newDecorations);
	}