Try to test a theoretical problem:

content/browser/web_contents/web_contents_impl.cc

 // Copyright (c) 2012 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/web_contents/web_contents_impl.h"
 
 #include <utility>
 
 #include "base/command_line.h"
 #include "base/debug/trace_event.h"
@@ skipping 2723 matching lines @@
   RenderFrameHostImpl* rfh =
       static_cast<RenderFrameHostImpl*>(render_frame_message_source_);
   FOR_EACH_OBSERVER(
       WebContentsObserver, observers_, DidFinishLoad(rfh, validated_url));
 }
 
 void WebContentsImpl::OnDidStartLoading(bool to_different_document) {
   RenderFrameHostImpl* rfh =
       static_cast<RenderFrameHostImpl*>(render_frame_message_source_);
   int64 render_frame_id = rfh->frame_tree_node()->frame_tree_node_id();
+  DLOG(INFO) << "WCI::OnDidStartLoading for " << rfh->GetSiteInstance()->GetSiteURL();
 
   // Any main frame load to a new document should reset the load progress, since
   // it will replace the current page and any frames.
   if (to_different_document && !rfh->GetParent()) {
     ResetLoadProgressState();
     loading_frames_in_progress_ = 0;
   }
 
   // It is possible to get multiple calls to OnDidStartLoading that don't have
   // corresponding calls to OnDidStopLoading:
@@ skipping 1627 matching lines @@
   node->render_manager()->ResumeResponseDeferredAtStart();
 }
 
 void WebContentsImpl::SetForceDisableOverscrollContent(bool force_disable) {
   force_disable_overscroll_content_ = force_disable;
   if (view_)
     view_->SetOverscrollControllerEnabled(CanOverscrollContent());
 }
 
 }  // namespace content