Separate the NTP app ordering from the app list app ordering

chrome/browser/extensions/extension_sorting.h

Index: chrome/browser/extensions/extension_sorting.h
diff --git a/chrome/browser/extensions/extension_sorting.h b/chrome/browser/extensions/extension_sorting.h
index f387095deb400e286aa2ce84f169929194986648..237c7daafe9f9ef26bc4f26e25f39e196164bce8 100644
--- a/chrome/browser/extensions/extension_sorting.h
+++ b/chrome/browser/extensions/extension_sorting.h
@@ -104,6 +104,10 @@ class ExtensionSorting {
   // Hidden extensions don't appear in the new tab page.
   void MarkExtensionAsHidden(const std::string& extension_id);
 
+  // Returns all extension ids in the sorting in an vector ordered according to
+  // this sorting.
+  void GetOrderedExtensionIds(extensions::ExtensionIdList* out) const;
+
  private:
   // The StringOrdinal is the app launch ordinal and the string is the extension
   // id.