src/vs/workbench/api/common/extHostExtensionService.ts/AbstractExtHostExtensionService/getExtensionPathIndex
class AbstractExtHostExtensionService:	public async getExtensionPathIndex(): Promise<ExtensionPaths> {
		if (!this._extensionPathIndex) {
			this._extensionPathIndex = this._createExtensionPathIndex(this._myRegistry.getAllExtensionDescriptions()).then((searchTree) => {
				return new ExtensionPaths(searchTree);
			});
		}
		return this._extensionPathIndex;
	}