src/vs/workbench/common/memento.ts/Memento/clear
class Memento:	static clear(scope: StorageScope): void {

		// Workspace
		if (scope === StorageScope.WORKSPACE) {
			Memento.workspaceMementos.clear();
		}

		// Global
		if (scope === StorageScope.GLOBAL) {
			Memento.globalMementos.clear();
		}
	}