src/vs/editor/common/services/markerDecorationsService.ts/MarkerDecorationsService/_onModelAdded
class MarkerDecorationsService:	private _onModelAdded(model: ITextModel): void {
		const markerDecorations = new MarkerDecorations(model);
		this._markerDecorations.set(model.uri, markerDecorations);
		this._updateDecorations(markerDecorations);
	}