Make chrome/ be documentElement/body agnostic with regards to scrollTop/Left

chrome/browser/resources/about_memory.js

Index: chrome/browser/resources/about_memory.js
diff --git a/chrome/browser/resources/about_memory.js b/chrome/browser/resources/about_memory.js
index e3a6871753b197f341c9781f12970c95bbc44671..0e4c62bf4a14cf41c943b78fc8e78401b4841d9a 100644
--- a/chrome/browser/resources/about_memory.js
+++ b/chrome/browser/resources/about_memory.js
@@ -42,12 +42,14 @@ function handleHelpTooltipMouseOver(event) {
   var width = el.offsetWidth;
   var height = el.offsetHeight;
 
-  if (event.pageX - width - 50 + document.documentElement.scrollLeft >= 0)
+  var scrollLeft = scrollLeftForDocument(document);
+  if (event.pageX - width - 50 + scrollLeft >= 0)
     el.style.left = (event.pageX - width - 20) + 'px';
   else
     el.style.left = (event.pageX + 20) + 'px';
 
-  if (event.pageY - height - 50 + document.documentElement.scrollTop >= 0)
+  var scrollTop = scrollTopForDocument(document);
+  if (event.pageY - height - 50 + scrollTop >= 0)
     el.style.top = (event.pageY - height - 20) + 'px';
   else
     el.style.top = (event.pageY + 20) + 'px';