src/vs/workbench/browser/parts/editor/editorPane.ts/EditorPane/getEditorMemento
class EditorPane:	protected getEditorMemento<T>(editorGroupService: IEditorGroupsService, key: string, limit: number = 10): IEditorMemento<T> {
		const mementoKey = `${this.getId()}${key}`;

		let editorMemento = EditorPane.EDITOR_MEMENTOS.get(mementoKey);
		if (!editorMemento) {
			editorMemento = new EditorMemento(this.getId(), key, this.getMemento(StorageScope.WORKSPACE, StorageTarget.MACHINE), limit, editorGroupService);
			EditorPane.EDITOR_MEMENTOS.set(mementoKey, editorMemento);
		}

		return editorMemento;
	}