Account for scroll when positioning the flakiness dashboard popup

Tools/TestResultServer/static-dashboards/ui.js

 // Copyright (C) 2013 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
 // copyright notice, this list of conditions and the following disclaimer
@@ skipping 40 matching lines @@
         document.addEventListener('mousedown', ui.popup._handleMouseDown, false);
     }
 
     // Set html first so that we can get accurate size metrics on the popup.
     popup.innerHTML = html;
 
     var targetRect = target.getBoundingClientRect();
 
     var x = Math.min(targetRect.left - 10, document.documentElement.clientWidth - popup.offsetWidth);
     x = Math.max(0, x);
-    popup.style.left = x + document.body.scrollLeft + 'px';
+    popup.style.left = x + window.pageXOffset + 'px';

[ojan, 2014/06/29 03:46:37]

This part of the web platform is so crufty. :(

 
     var y = targetRect.top + targetRect.height;
     if (y + popup.offsetHeight > document.documentElement.clientHeight)
         y = targetRect.top - popup.offsetHeight;
     y = Math.max(0, y);
-    popup.style.top = y + document.body.scrollTop + 'px';
+    popup.style.top = y + window.pageYOffset + 'px';
 }
 
 ui.popup._handleMouseDown = function(e) {
     // Clear the open popup, unless the click was inside the popup.
     var popup = $('popup');
     if (popup && e.target != popup && !(popup.compareDocumentPosition(e.target) & 16))
         ui.popup.hide();
 }
 
 ui.html = {};
@@ skipping 143 matching lines @@
     {
         this._messages += message + '<br>';
     },
     hasErrors: function()
     {
         return !!this._messages;
     }
 }
 
 })();