Fix initial erroneous navigation in iframe to not add history entry.

content/renderer/render_view_impl.cc

Index: content/renderer/render_view_impl.cc
diff --git a/content/renderer/render_view_impl.cc b/content/renderer/render_view_impl.cc
index 7f2172b76eafde1f96ae015c7bbe1a412344aa27..cbca1adcfe14831f22cc781c2a1c11900ecb6a63 100644
--- a/content/renderer/render_view_impl.cc
+++ b/content/renderer/render_view_impl.cc
@@ -3417,7 +3417,8 @@ void RenderViewImpl::didStartProvisionalLoad(WebFrame* frame) {
 
     // Make sure redirect tracking state is clear for the new load.
     completed_client_redirect_src_ = Referrer();
-  } else if (frame->parent()->isLoading()) {
+  } else if (frame->parent()->isLoading() ||
+      document_state->navigation_state()->pending_page_id() == -1) {

[Charlie Reis, 2013/05/23 21:53:33]

It's hard to tell whether this fix is correct, since it's not clear how these
conditions relate to each other.

What's the goal here?  Is it that all initial iframe navigations should be
considered auto-subframe?  Is pending_page_id() == -1 a good indicator of that? 
If so, do we still need the isLoading clause?

Maybe a comment about what cases this is trying to address would help.

[nasko, 2013/09/20 21:25:39]

This is now completely rewritten.

     // Take note of AUTO_SUBFRAME loads here, so that we can know how to
     // load an error page.  See didFailProvisionalLoad.
     document_state->navigation_state()->set_transition_type(