src/vs/platform/extensionManagement/common/extensionStorage.ts/ExtensionStorageService/getExtensionId
class ExtensionStorageService:	private getExtensionId(extension: IExtension | IGalleryExtension | string): string {
		if (isString(extension)) {
			return extension;
		}
		const publisher = (extension as IExtension).manifest ? (extension as IExtension).manifest.publisher : (extension as IGalleryExtension).publisher;
		const name = (extension as IExtension).manifest ? (extension as IExtension).manifest.name : (extension as IGalleryExtension).name;
		return getExtensionId(publisher, name);
	}