InstantExtended: Transient naventry for preview.

content/public/browser/navigation_controller.h

Index: content/public/browser/navigation_controller.h
diff --git a/content/public/browser/navigation_controller.h b/content/public/browser/navigation_controller.h
index d37960b13e952b066a63e39f2fec4f6995f18ca8..b2b82a3bc599f84745b7096d8c5e0f73ff0ec246 100644
--- a/content/public/browser/navigation_controller.h
+++ b/content/public/browser/navigation_controller.h
@@ -265,6 +265,15 @@ class NavigationController {
   // by the navigation controller and may be deleted at any time.
   virtual NavigationEntry* GetTransientEntry() const = 0;
 
+  // Adds an entry that is returned by GetActiveEntry(). The entry is
+  // transient: any navigation causes it to be removed and discarded.  The
+  // NavigationController becomes the owner of |entry| and deletes it when
+  // it discards it. This is useful with interstitial page that need to be
+  // represented as an entry, but should go away when the user navigates away
+  // from them.
+  // Note that adding a transient entry does not change the active contents.
+  virtual void AddTransientEntry(NavigationEntry* entry) = 0;
+
   // New navigations -----------------------------------------------------------
 
   // Loads the specified URL, specifying extra http headers to add to the