Create FrameNavigationEntries for the initial blank page in subframes.

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 <queue>
 
 #include "base/metrics/histogram.h"
 #include "base/strings/string_util.h"
@@ skipping 523 matching lines @@
                                                 const GURL& url,
                                                 const Referrer& referrer,
                                                 const PageState& page_state) {
   // 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.
-    // However, we may see commits of subframes when their parent or ancestor is
-    // still the initial about:blank page, and we don't currently keep a
-    // FrameNavigationEntry for that.  We ignore such commits, similar to how we
-    // handle them at the top level.
-    // TODO(creis): Consider creating FNEs for initial about:blank commits.
+    // TODO(creis): Kill the renderer if we get here.
+    NOTREACHED() << "Shouldn't see a commit for a subframe before parent.";
     return;
   }
 
   // Now check whether we have a TreeNode for the node itself.
   int frame_tree_node_id = frame_tree_node->frame_tree_node_id();
   for (TreeNode* child : parent_node->children) {
     if (child->frame_entry->frame_tree_node_id() == frame_tree_node_id) {
       // Update the existing FrameNavigationEntry (e.g., for replaceState).
       child->frame_entry->UpdateEntry(item_sequence_number,
                                       document_sequence_number, site_instance,
                                       url, referrer, page_state);
       return;
     }
   }
 
-  // No entry exists yet, so create a new one unless it's for about:blank.
+  // No entry exists yet, so create a new one.
   // Unordered list, since we expect to look up entries by frame sequence number
   // or unique name.
-  if (url == GURL(url::kAboutBlankURL))
-    return;
   FrameNavigationEntry* frame_entry = new FrameNavigationEntry(
       frame_tree_node_id, item_sequence_number, document_sequence_number,
       site_instance, url, referrer);
   frame_entry->set_page_state(page_state);
   parent_node->children.push_back(
       new NavigationEntryImpl::TreeNode(frame_entry));
 }
 
 FrameNavigationEntry* NavigationEntryImpl::GetFrameEntry(
     FrameTreeNode* frame_tree_node) const {
@@ skipping 27 matching lines @@
       return node;
     }
     // Enqueue any children and keep looking.
     for (auto& child : node->children)
       work_queue.push(child);
   }
   return nullptr;
 }
 
 }  // namespace content