Relax self-referential frame checks for non-initial navigations.

content/browser/frame_host/navigation_handle_impl.cc

 // Copyright 2015 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_handle_impl.h"
 
 #include <iterator>
 
 #include "base/logging.h"
 #include "content/browser/appcache/appcache_navigation_handle.h"
@@ skipping 957 matching lines @@
   // about: URLs should be exempted since they are reserved for other purposes
   // and cannot be the source of infinite recursion. See
   // https://crbug.com/341858 .
   if (url_.SchemeIs("about"))
     return false;
 
   // Browser-triggered navigations should be exempted.
   if (!is_renderer_initiated_)
     return false;
 
+  // Only enforce this for initial navigations in frames.  This handles
+  // the common cases of developers shooting themselves in the foot, but allows
+  // frames to deliberately navigate themselves to a self-referential URL
+  // after being created.  For example, some sites construct frame hierarchies
+  // with frames that navigate to the same URL via POSTs. See
+  // https://crbug.com/710008.
+  if (frame_tree_node_->has_committed_real_load())
+    return false;
+
   // We allow one level of self-reference because some sites depend on that,
   // but we don't allow more than one.
   bool found_self_reference = false;
   for (const FrameTreeNode* node = frame_tree_node_->parent(); node;
        node = node->parent()) {
     if (node->current_url().EqualsIgnoringRef(url_)) {
       if (found_self_reference)
         return true;
       found_self_reference = true;
     }
   }
   return false;
 }
 
 }  // namespace content