Fix DnD jank...

chrome/browser/resources/new_new_tab.js

Index: chrome/browser/resources/new_new_tab.js
===================================================================
--- chrome/browser/resources/new_new_tab.js	(revision 20158)
+++ chrome/browser/resources/new_new_tab.js	(working copy)
@@ -1055,6 +1055,12 @@
 
 // Tooltip for elements that have text that overflows.
 document.addEventListener('mouseover', function(e) {
+  // We don't want to do this while we are dragging because it makes things very
+  // janky
+  if (dnd.dragItem) {
+    return;
+  }
+
   var el = findAncestor(e.target, function(el) {
     return el.xtitle;
   });