OOPIF: Fix subframe back/forward after recreating FTNs (try #2).

content/browser/frame_host/navigator_impl.cc

Index: content/browser/frame_host/navigator_impl.cc
diff --git a/content/browser/frame_host/navigator_impl.cc b/content/browser/frame_host/navigator_impl.cc
index e7d9de64b70c2b7ffff9a5e776cbfed02a8f311f..c953cfa262905d3df245a2003a781063d5accba0 100644
--- a/content/browser/frame_host/navigator_impl.cc
+++ b/content/browser/frame_host/navigator_impl.cc
@@ -440,17 +440,17 @@ bool NavigatorImpl::NavigateNewChildFrame(
   if (!entry)
     return false;
 
+  // TODO(creis): Remove unique_name from the IPC, now that we can rely on the
+  // replication state.
+  DCHECK_EQ(render_frame_host->frame_tree_node()
+                ->current_replication_state()
+                .unique_name,
+            unique_name);
   FrameNavigationEntry* frame_entry =
-      entry->GetFrameEntryByUniqueName(unique_name);
+      entry->GetFrameEntry(render_frame_host->frame_tree_node());
   if (!frame_entry)
     return false;
 
-  // Update the FrameNavigationEntry's FrameTreeNode ID (which is currently the
-  // ID of the old FrameTreeNode that no longer exists) to be the ID of the
-  // newly created frame.
-  frame_entry->set_frame_tree_node_id(
-      render_frame_host->frame_tree_node()->frame_tree_node_id());
-
   return NavigateToEntry(render_frame_host->frame_tree_node(), *frame_entry,
                          *entry, NavigationControllerImpl::NO_RELOAD, false,
                          false);