src/vs/workbench/services/extensionManagement/common/webExtensionsScannerService.ts/WebExtensionsScannerService/addExtensionFromGallery
class WebExtensionsScannerService:	async addExtensionFromGallery(galleryExtension: IGalleryExtension): Promise<IExtension> {
		if (!this.canAddExtension(galleryExtension)) {
			throw new Error(localize('cannot be added', "Cannot add gallery extension '{0}'.", galleryExtension.displayName || galleryExtension.name));
		}

		const webExtension = await this.toWebExtensionFromGallery(galleryExtension);
		return this.addWebExtension(webExtension);
	}