Don't take parent in webview ctor

src/vs/workbench/parts/extensions/browser/extensionEditor.ts

@@ -426,7 +426,8 @@ export class ExtensionEditor extends BaseEditor {
 			.then<void>(body => {
 				const allowedBadgeProviders = this.extensionsWorkbenchService.allowedBadgeProviders;
 				const webViewOptions = allowedBadgeProviders.length > 0 ? { allowScripts: false, allowSvgs: false, svgWhiteList: allowedBadgeProviders } : {};
-				this.activeWebview = new Webview(this.content, this.partService.getContainer(Parts.EDITOR_PART), this.themeService, this.environmentService, this.contextViewService, this.contextKey, this.findInputFocusContextKey, webViewOptions);
+				this.activeWebview = new Webview(this.partService.getContainer(Parts.EDITOR_PART), this.themeService, this.environmentService, this.contextViewService, this.contextKey, this.findInputFocusContextKey, webViewOptions);
+				this.activeWebview.mountTo(this.content);
 				const removeLayoutParticipant = arrays.insert(this.layoutParticipants, this.activeWebview);
 				this.contentDisposables.push(toDisposable(removeLayoutParticipant));
 				this.activeWebview.contents = body;

src/vs/workbench/parts/html/browser/htmlPreviewPart.ts

@@ -93,7 +93,6 @@ export class HtmlPreviewPart extends BaseWebviewEditor {
 			}
 
 			this._webview = new Webview(
-				this.content,
 				this.partService.getContainer(Parts.EDITOR_PART),
 				this.themeService,
 				this._environmentService,
@@ -104,6 +103,7 @@ export class HtmlPreviewPart extends BaseWebviewEditor {
 					...webviewOptions,
 					useSameOriginForRoot: true
 				});
+			this._webview.mountTo(this.content);
 
 			if (this.input && this.input instanceof HtmlInput) {
 				const state = this.loadViewState(this.input.getResource());

src/vs/workbench/parts/html/browser/webview.ts

@@ -37,7 +37,6 @@ export class Webview {
 	private _contents: string = '';
 
 	constructor(
-		private readonly parent: HTMLElement,
 		private readonly _styleElement: Element,
 		private readonly _themeService: IThemeService,
 		private readonly _environmentService: IEnvironmentService,
@@ -180,11 +179,11 @@ export class Webview {
 
 		this.style(this._themeService.getTheme());
 		this._themeService.onThemeChange(this.style, this, this._disposables);
+	}
 
-		if (parent) {
-			parent.appendChild(this._webviewFindWidget.getDomNode());
-			parent.appendChild(this._webview);
-		}
+	public mountTo(parent: HTMLElement) {
+		parent.appendChild(this._webviewFindWidget.getDomNode());
+		parent.appendChild(this._webview);
 	}
 
 	public notifyFindWidgetFocusChanged(isFocused: boolean) {
@@ -293,9 +292,12 @@ export class Webview {
 			}
 
 			contents.setZoomFactor(factor);
+			if (!this._webview || !this._webview.parentElement) {
+				return;
+			}
 
-			const width = this.parent.clientWidth;
-			const height = this.parent.clientHeight;
+			const width = this._webview.parentElement.clientWidth;
+			const height = this._webview.parentElement.clientHeight;
 			contents.setSize({
 				normal: {
 					width: Math.floor(width * factor),

src/vs/workbench/parts/webview/electron-browser/webviewEditor.ts

@@ -191,7 +191,6 @@ export class WebviewEditor extends BaseWebviewEditor {
 		this.findWidgetVisible = KEYBINDING_CONTEXT_WEBVIEW_FIND_WIDGET_VISIBLE.bindTo(this._contextKeyService);
 
 		this._webview = new Webview(
-			this.webviewContent,
 			this._partService.getContainer(Parts.EDITOR_PART),
 			this.themeService,
 			this._environmentService,
@@ -202,6 +201,7 @@ export class WebviewEditor extends BaseWebviewEditor {
 				enableWrappedPostMessage: true,
 				useSameOriginForRoot: false
 			});
+		this._webview.mountTo(this.webviewContent);
 		input.webview = this._webview;
 
 		if (input.options.tryRestoreScrollPosition) {