Do not assign launch ordinals to ephemeral apps

extensions/browser/app_sorting.h

 // Copyright (c) 2013 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #ifndef EXTENSIONS_BROWSER_APP_SORTING_H_
 #define EXTENSIONS_BROWSER_APP_SORTING_H_
 
 #include <string>
 
 #include "base/basictypes.h"
@@ skipping 91 matching lines @@
   // Convert the page StringOrdinal value to its integer equivalent. This takes
   // O(# of apps) worst-case.
   virtual int PageStringOrdinalAsInteger(
       const syncer::StringOrdinal& page_ordinal) const = 0;
 
   // Converts the page index integer to its StringOrdinal equivalent. This takes
   // O(# of apps) worst-case.
   virtual syncer::StringOrdinal PageIntegerAsStringOrdinal(
       size_t page_index) = 0;
 
-  // Hidden extensions don't appear in the new tab page.
-  virtual void MarkExtensionAsHidden(const std::string& extension_id) = 0;
+  // Sets whether the extension should be visible in the new tab page.

[tapted, 2014/07/17 04:29:46]

Perhaps, 

// Hides an extension from the new tab page, or makes a previously hidden
// extension visible.

[tmdiep, 2014/07/17 05:48:57]

Done.

+  virtual void SetExtensionVisible(const std::string& extension_id,
+                                   bool visible) = 0;
 
  private:
   DISALLOW_COPY_AND_ASSIGN(AppSorting);
 };
 
 }  // namespace extensions
 
 #endif  // EXTENSIONS_BROWSER_APP_SORTING_H_