Do not assign launch ordinals to ephemeral apps

chrome/browser/extensions/chrome_app_sorting.cc

 // Copyright 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.
 
 #include "chrome/browser/extensions/chrome_app_sorting.h"
 
 #include <algorithm>
 #include <vector>
 
 #include "chrome/browser/chrome_notification_types.h"
@@ skipping 417 matching lines @@
   if (page_index < ntp_ordinal_map_.size()) {
     PageOrdinalMap::const_iterator it = ntp_ordinal_map_.begin();
     std::advance(it, page_index);
     return it->first;
   }
 
   CreateOrdinalsIfNecessary(page_index + 1);
   return ntp_ordinal_map_.rbegin()->first;
 }
 
-void ChromeAppSorting::MarkExtensionAsHidden(const std::string& extension_id) {
-  ntp_hidden_extensions_.insert(extension_id);
+void ChromeAppSorting::SetExtensionVisible(const std::string& extension_id,
+                                           bool visible) {
+  if (visible)
+    ntp_hidden_extensions_.erase(extension_id);
+  else
+    ntp_hidden_extensions_.insert(extension_id);
 }
 
 syncer::StringOrdinal ChromeAppSorting::GetMinOrMaxAppLaunchOrdinalsOnPage(
     const syncer::StringOrdinal& target_page_ordinal,
     AppLaunchOrdinalReturn return_type) const {
   CHECK(target_page_ordinal.IsValid());
 
   syncer::StringOrdinal return_value;
 
   PageOrdinalMap::const_iterator page =
@@ skipping 164 matching lines @@
   for (AppLaunchOrdinalMap::const_iterator it = m.begin(); it != m.end();
        ++it) {
     const std::string& id = it->second;
     if (ntp_hidden_extensions_.count(id) == 0)
       result++;
   }
   return result;
 }
 
 }  // namespace extensions