Create FrameNavigationEntries for the initial blank page in subframes.

content/browser/frame_host/navigation_controller_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.
 
 /*
  * Copyright (C) 2006, 2007, 2008, 2009 Apple Inc. All rights reserved.
  * Copyright (C) 2008 Nokia Corporation and/or its subsidiary(-ies)
  * Copyright (C) 2008, 2009 Torch Mobile Inc. All rights reserved.
  *     (http://www.torchmobile.com/)
  *
@@ skipping 396 matching lines @@
   int index = GetEntryIndexWithPageID(instance, page_id);
   return (index != -1) ? entries_[index] : nullptr;
 }
 
 NavigationEntryImpl*
 NavigationControllerImpl::GetEntryWithUniqueID(int nav_entry_id) const {
   int index = GetEntryIndexWithUniqueID(nav_entry_id);
   return (index != -1) ? entries_[index] : nullptr;
 }
 
-bool NavigationControllerImpl::HasCommittedRealLoad(
-    FrameTreeNode* frame_tree_node) const {
-  NavigationEntryImpl* last_committed = GetLastCommittedEntry();
-  return last_committed && last_committed->GetFrameEntry(frame_tree_node);
-}
-
 void NavigationControllerImpl::LoadEntry(
     scoped_ptr<NavigationEntryImpl> entry) {
   // When navigating to a new page, we don't know for sure if we will actually
   // end up leaving the current page.  The new page load could for example
   // result in a download or a 'no content' response (e.g., a mailto: URL).
   SetPendingEntry(entry.Pass());
   NavigateToPendingEntry(NO_RELOAD);
 }
 
 void NavigationControllerImpl::SetPendingEntry(
@@ skipping 525 matching lines @@
     if (!rfh->GetParent()) {
       return NAVIGATION_TYPE_NEW_PAGE;
     }
 
     // When this is a new subframe navigation, we should have a committed page
     // in which it's a subframe. This may not be the case when an iframe is
     // navigated on a popup navigated to about:blank (the iframe would be
     // written into the popup by script on the main page). For these cases,
     // there isn't any navigation stuff we can do, so just ignore it.
     if (!GetLastCommittedEntry())
       return NAVIGATION_TYPE_NAV_IGNORE;

[Charlie Reis, 2015/07/23 19:57:34]

I think all the IGNORE cases here are when the main frame has no NavigationEntry
for the initial blank page.  That's worth revisiting as well, but in this CL I'm
only changing whether subframes have FNEs for the initial blank page.

[Avi (use Gerrit), 2015/07/23 20:27:58]

What horrible edge case is it where the there is no last-committed entry but
it's not the initial blank page?
Fair enough.

[Charlie Reis, 2015/07/23 22:02:22]

Sorry, reparse that as "when the main frame has no NavigationEntry, which means
it's on the initial blank page."  There's no case where it's on a real page but
doesn't have a last committed entry.

 
     // Valid subframe navigation.
     return NAVIGATION_TYPE_NEW_SUBFRAME;
   }
 
   // We only clear the session history when navigating to a new page.
   DCHECK(!params.history_list_was_cleared);
 
   if (rfh->GetParent()) {
     // All manual subframes would be did_create_new_entry and handled above, so
@@ skipping 1009 matching lines @@
     }
   }
 }
 
 void NavigationControllerImpl::SetGetTimestampCallbackForTest(
     const base::Callback<base::Time()>& get_timestamp_callback) {
   get_timestamp_callback_ = get_timestamp_callback;
 }
 
 }  // namespace content