src/vs/workbench/contrib/themes/browser/themes.contribution.ts/MarketplaceThemesPicker/installExtension
class MarketplaceThemesPicker:	private async installExtension(galleryExtension: IGalleryExtension) {
		try {
			openExtensionViewlet(this.paneCompositeService, `@id:${galleryExtension.identifier.id}`);
			await this.progressService.withProgress({
				location: ProgressLocation.Notification,
				title: localize('installing extensions', "Installing Extension {0}...", galleryExtension.displayName)
			}, async () => {
				await this.extensionManagementService.installFromGallery(galleryExtension);
			});
			return true;
		} catch (e) {
			this.logService.error(`Problem installing extension ${galleryExtension.identifier.id}`, e);
			return false;
		}
	}