Merge 93868 - Web Inspector: in some cases Popover code is failing to calculate popover box posit...

Source/WebCore/inspector/front-end/Popover.js

 /*
  * Copyright (C) 2009 Google Inc. All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions are
  * met:
  *
  *     * Redistributions of source code must retain the above copyright
  * notice, this list of conditions and the following disclaimer.
  *     * Redistributions in binary form must reproduce the above
@@ skipping 76 matching lines @@
         const borderRadius = 10;
 
         // Skinny tooltips are not pretty, their arrow location is not nice.
         preferredWidth = Math.max(preferredWidth, 50);
         const totalWidth = window.innerWidth;
         const totalHeight = window.innerHeight;
 
         var anchorBox = anchorElement.offsetRelativeToWindow(window);
         anchorBox.width = anchorElement.offsetWidth;
         anchorBox.height = anchorElement.offsetHeight;
-        while (anchorElement !== anchorElement.ownerDocument.body) {
+        while (anchorElement && anchorElement !== anchorElement.ownerDocument.body) {
             if (anchorElement.scrollLeft)
                 anchorBox.x -= anchorElement.scrollLeft;
             if (anchorElement.scrollTop)
                 anchorBox.y -= anchorElement.scrollTop;
             anchorElement = anchorElement.parentElement;
         }
 
         var newElementPosition = { x: 0, y: 0, width: preferredWidth + scrollerWidth, height: preferredHeight };
 
         var verticalAlignment;
@@ skipping 144 matching lines @@
         if (this._hidePopupTimer) {
             clearTimeout(this._hidePopupTimer);
             delete this._hidePopupTimer;
 
             // We know that we reached the popup, but we might have moved over other elements.
             // Discard pending command.
             this._resetHoverTimer();
         }
     }
 }