src/vs/editor/browser/widget/codeEditorWidget.ts/CodeEditorWidget/deltaDecorations
class CodeEditorWidget:	public deltaDecorations(oldDecorations: string[], newDecorations: IModelDeltaDecoration[]): string[] {
		if (!this._modelData) {
			return [];
		}

		if (oldDecorations.length === 0 && newDecorations.length === 0) {
			return oldDecorations;
		}

		return this._modelData.model.deltaDecorations(oldDecorations, newDecorations, this._id);
	}