src/vs/workbench/api/common/extHostWebview.ts/ExtHostWebviews/createNewWebview
class ExtHostWebviews:	public createNewWebview(handle: string, options: extHostProtocol.IWebviewContentOptions, extension: IExtensionDescription): ExtHostWebview {
		const webview = new ExtHostWebview(handle, this._webviewProxy, reviveOptions(options), this.remoteInfo, this.workspace, extension, this._deprecationService);
		this._webviews.set(handle, webview);

		webview._onDidDispose(() => { this._webviews.delete(handle); });

		return webview;
	}