Fix regression where rows could become non-focusable.

chrome/browser/resources/extensions/extension_list.js

Index: chrome/browser/resources/extensions/extension_list.js
diff --git a/chrome/browser/resources/extensions/extension_list.js b/chrome/browser/resources/extensions/extension_list.js
index 0b3e4605be900579600d8f70e25979f9c1db02ab..327dd42bcb4f2cd4ca2ff269003214a3f4dc7411 100644
--- a/chrome/browser/resources/extensions/extension_list.js
+++ b/chrome/browser/resources/extensions/extension_list.js
@@ -273,14 +273,19 @@ cr.define('extensions', function() {
           case EventType.ERROR_ADDED:
           case EventType.ERRORS_REMOVED:
           case EventType.PREFS_CHANGED:
-            if (eventData.extensionInfo)
+            if (eventData.extensionInfo) {
               this.updateExtension_(eventData.extensionInfo);
+              this.focusGrid_.ensureRowActive();
+            }
             break;
           case EventType.UNINSTALLED:
             var index = this.getIndexOfExtension_(eventData.item_id);
             this.extensions_.splice(index, 1);
             var childNode = $(eventData.item_id);
             childNode.parentNode.removeChild(childNode);
+            this.focusGrid_.removeRow(assertInstanceof(childNode,
+                                                       ExtensionFocusRow));
+            this.focusGrid_.ensureRowActive();
             break;
           default:
             assertNotReached();
@@ -389,9 +394,6 @@ cr.define('extensions', function() {
      * @private
      */
     showExtensionNodes_: function() {
-      // Remove the rows from |focusGrid_| without destroying them.
-      this.focusGrid_.rows.length = 0;

[Dan Beam, 2015/05/12 01:28:42]

why could we just clear this but can't now?

[hcarmona, 2015/05/12 02:00:47]

This function used to be called every time the grid was updated. Now,
this is called only when the list is created which means it will only be
called once. Doesn't make sense to clear it any more.

-
       // Any node that is not updated will be removed.
       var seenIds = [];
 
@@ -669,6 +671,10 @@ cr.define('extensions', function() {
       // Maintain the order that nodes should be in when creating as well as
       // when adding only one new row.
       this.insertBefore(row, nextNode);
+      var nextRow = null;
+      if (nextNode)
+        nextRow = assertInstanceof(nextNode, ExtensionFocusRow);
+      this.focusGrid_.addRowBefore(row, nextRow);
       this.updateNode_(extension, row);

[Dan Beam, 2015/05/12 01:28:42]

needs more \n

[hcarmona, 2015/05/12 02:00:47]

Done.

     },
 
@@ -1025,7 +1031,6 @@ cr.define('extensions', function() {
       }
 
       row.updateFocusableElements();
-      this.focusGrid_.addRow(row);
     },
 
     /**