Enable swapping a frame back in to its parent process

content/browser/frame_host/render_frame_host_manager.h

Index: content/browser/frame_host/render_frame_host_manager.h
diff --git a/content/browser/frame_host/render_frame_host_manager.h b/content/browser/frame_host/render_frame_host_manager.h
index 38c50ddfcbf6aacb9bd8dbf2c75b2dcb9f957622..7394628bcbf3136c133ebe367c0852818915106c 100644
--- a/content/browser/frame_host/render_frame_host_manager.h
+++ b/content/browser/frame_host/render_frame_host_manager.h
@@ -123,7 +123,8 @@ class CONTENT_EXPORT RenderFrameHostManager : public NotificationObserver {
         bool for_main_frame_navigation) = 0;
     virtual bool CreateRenderFrameForRenderManager(
         RenderFrameHost* render_frame_host,
-        int parent_routing_id) = 0;
+        int parent_routing_id,
+        int proxy_routing_id) = 0;
     virtual void BeforeUnloadFiredFromRenderManager(
         bool proceed, const base::TimeTicks& proceed_time,
         bool* proceed_to_fire_unload) = 0;
@@ -431,6 +432,12 @@ class CONTENT_EXPORT RenderFrameHostManager : public NotificationObserver {
       SiteInstance* current_instance,
       bool force_browsing_instance_swap);
 
+  // Determines the appropriate url to use as the current url for SiteInstance
+  // selection.
+  const GURL& GetCurrentURLForSiteInstance(
+      SiteInstance* current_instance,
+      NavigationEntry* current_entry);
+
   // Creates a new RenderFrameHostImpl for the |new_instance| while respecting
   // the opener route if needed and stores it in pending_render_frame_host_.
   void CreateRenderFrameHostForNewSiteInstance(