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

content/browser/frame_host/navigation_handle_impl.cc

Index: content/browser/frame_host/navigation_handle_impl.cc
diff --git a/content/browser/frame_host/navigation_handle_impl.cc b/content/browser/frame_host/navigation_handle_impl.cc
index 46866467c1b8cdbff04a4724cd1a56569396b7e6..ea15872bb81478197ea7cea00d3aee278d85abd4 100644
--- a/content/browser/frame_host/navigation_handle_impl.cc
+++ b/content/browser/frame_host/navigation_handle_impl.cc
@@ -975,6 +975,15 @@ bool NavigationHandleImpl::IsSelfReferentialURL() {
   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;