ui/list.js: prevent from position calculation with wrong position.

chrome/browser/resources/shared/js/cr/ui/list.js

Index: chrome/browser/resources/shared/js/cr/ui/list.js
diff --git a/chrome/browser/resources/shared/js/cr/ui/list.js b/chrome/browser/resources/shared/js/cr/ui/list.js
index 3d6d0c3f138af7979d388949ee4273c07aa61ca1..dc4f91a9f16e7dfe63d305260a07088e5f0231d2 100644
--- a/chrome/browser/resources/shared/js/cr/ui/list.js
+++ b/chrome/browser/resources/shared/js/cr/ui/list.js
@@ -1048,6 +1048,10 @@ cr.define('cr.ui', function() {
         return;
       }
 
+      // Save the previous positions before any manipulation of elements.
+      var scrollTop = this.scrollTop;
+      var clientHeight = this.clientHeight;
+
       // Store all the item sizes into the cache in advance, to prevent
       // interleave measuring with mutating dom.
       if (!this.fixedHeight_)
@@ -1059,8 +1063,6 @@ cr.define('cr.ui', function() {
       var newCachedItems = {};
 
       var autoExpands = this.autoExpands_;
-      var scrollTop = this.scrollTop;
-      var clientHeight = this.clientHeight;
 
       var itemsInViewPort = this.getItemsInViewPort(scrollTop, clientHeight);
       // Draws the hidden rows just above/below the viewport to prevent