Ensure FrameNavigationEntry is fully updated.

content/browser/frame_host/navigation_entry_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/navigation_entry_impl.h"
 
 #include <stddef.h>
 
 #include <queue>
 #include <utility>
@@ skipping 679 matching lines @@
     FrameTreeNode* frame_tree_node,
     int64_t item_sequence_number,
     int64_t document_sequence_number,
     SiteInstanceImpl* site_instance,
     scoped_refptr<SiteInstanceImpl> source_site_instance,
     const GURL& url,
     const Referrer& referrer,
     const PageState& page_state,
     const std::string& method,
     int64_t post_id) {
+  // We should only have an empty PageState if the navigation is new, and thus
+  // page ID is -1.
+  if (!page_state.IsValid() && GetPageID() != -1) {
+    // Temporarily generate a minidump to diagnose https://crbug.com/568703.
+    base::debug::DumpWithoutCrashing();
+    NOTREACHED() << "Shouldn't set an empty PageState.";
+  }
+
+  // If this is called for the main frame, the FrameNavigationEntry is
+  // guaranteed to exist, so just update it directly and return.
+  if (frame_tree_node->IsMainFrame()) {
+    // If the document of the FrameNavigationEntry is changing, we must clear
+    // any child FrameNavigationEntries.
+    if (root_node()->frame_entry->document_sequence_number() !=
+        document_sequence_number)
+      root_node()->children.clear();
+
+    root_node()->frame_entry->UpdateEntry(
+        frame_tree_node->unique_name(), item_sequence_number,
+        document_sequence_number, site_instance,
+        std::move(source_site_instance), url, referrer, page_state, method,
+        post_id);
+    return;
+  }
+
   // We should already have a TreeNode for the parent node by the time this node
   // commits.  Find it first.
-  DCHECK(frame_tree_node->parent());
   NavigationEntryImpl::TreeNode* parent_node =
       FindFrameEntry(frame_tree_node->parent());
   if (!parent_node) {
     // The renderer should not send a commit for a subframe before its parent.
     // TODO(creis): Kill the renderer if we get here.
     return;
   }
 
   // Now check whether we have a TreeNode for the node itself.
   const std::string& unique_name = frame_tree_node->unique_name();
@@ skipping 49 matching lines @@
       return node;
 
     // Enqueue any children and keep looking.
     for (auto& child : node->children)
       work_queue.push(child);
   }
   return nullptr;
 }
 
 }  // namespace content