DevTools: fix network grid scroll to bottom, render group node frame icon.

third_party/WebKit/Source/devtools/front_end/network/NetworkFrameGrouper.js

 // Copyright 2017 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 {Network.GroupLookupInterface}
  */
 Network.NetworkFrameGrouper = class {
   /**
    * @param {!Network.NetworkLogView} parentView
@@ skipping 58 matching lines @@
 
   /**
    * @override
    * @param {!Element} cell
    * @param {string} columnId
    */
   renderCell(cell, columnId) {
     super.renderCell(cell, columnId);
     if (columnId === 'name') {
       var name = this.displayName();
-      if (!this._productBadge)
+      if (!this._productBadge) {
         this._productBadge = this.parentView().badgePool.badgeForFrame(this._frame);
+        this._productBadge.classList.add('network-frame-group-badge');
+      }
+      cell.appendChild(UI.Icon.create('largeicon-navigator-frame', 'network-frame-group-icon'));
       cell.appendChild(this._productBadge);
       cell.createTextChild(name);
       cell.title = name;
     }
   }
 };