Revert of OOPIF: Fix subframe back/forward after recreating FTNs.

content/browser/frame_host/navigator_impl.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 "content/browser/frame_host/navigator_impl.h"
 
 #include <utility>
 
 #include "base/metrics/histogram.h"
 #include "base/time/time.h"
@@ skipping 417 matching lines @@
 }
 
 bool NavigatorImpl::NavigateNewChildFrame(
     RenderFrameHostImpl* render_frame_host,
     const std::string& unique_name) {
   NavigationEntryImpl* entry =
       controller_->GetEntryWithUniqueID(render_frame_host->nav_entry_id());
   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->GetFrameEntry(render_frame_host->frame_tree_node());
+      entry->GetFrameEntryByUniqueName(unique_name);
   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);
 }
 
 void NavigatorImpl::DidNavigate(
     RenderFrameHostImpl* render_frame_host,
     const FrameHostMsg_DidCommitProvisionalLoad_Params& params) {
   FrameTree* frame_tree = render_frame_host->frame_tree_node()->frame_tree();
   bool oopifs_possible = SiteIsolationPolicy::AreCrossProcessFramesPossible();
@@ skipping 631 matching lines @@
   if (pending_entry != controller_->GetVisibleEntry() ||
       !should_preserve_entry) {
     controller_->DiscardPendingEntry(true);
 
     // Also force the UI to refresh.
     controller_->delegate()->NotifyNavigationStateChanged(INVALIDATE_TYPE_URL);
   }
 }
 
 }  // namespace content