[DevTools] Fix UI.EmptyWidget scrollbars

third_party/WebKit/Source/devtools/front_end/resources/AppManifestView.js

 // Copyright (c) 2016 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 /**
  * @implements {SDK.SDKModelObserver<!SDK.ResourceTreeModel>}
  * @unrestricted
  */
 Resources.AppManifestView = class extends UI.VBox {
   constructor() {
     super(true);
     this.registerRequiredCSS('resources/appManifestView.css');
 
+    this.contentElement.classList.add('overflow-overlay');
     this._emptyView = new UI.EmptyWidget(Common.UIString('No manifest detected'));
     var p = this._emptyView.appendParagraph();
     var linkElement = UI.createExternalLink('https://developers.google.com/web/fundamentals/engage-and-retain/web-app-manifest/?utm_source=devtools',
         Common.UIString('Read more about the web manifest'));
     p.appendChild(UI.formatLocalized('A web manifest allows you to control how your app behaves when launched and displayed to the user. %s', [linkElement]));
 
     this._emptyView.show(this.contentElement);
     this._emptyView.hideWidget();
 
     this._reportView = new UI.ReportView(Common.UIString('App Manifest'));
@@ skipping 134 matching lines @@
    * @param {!Common.Event} event
    */
   _addToHomescreen(event) {
     var target = SDK.targetManager.mainTarget();
     if (target && target.hasBrowserCapability()) {
       target.pageAgent().requestAppBanner();
       Common.console.show();
     }
   }
 };