RenderFlexibleBox should be treated as a candidate for visible position.

Source/core/dom/Position.cpp

 /*
  * Copyright (C) 2004, 2005, 2006, 2009 Apple Inc. All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions
  * are met:
  * 1. Redistributions of source code must retain the above copyright
  *    notice, this list of conditions and the following disclaimer.
  * 2. Redistributions in binary form must reproduce the above copyright
  *    notice, this list of conditions and the following disclaimer in the
@@ skipping 837 matching lines @@
         // associated renderer returns isText() true, e.g. RenderSVGInlineText.
         return false;
     }
 
     if (isRenderedHTMLTableElement(deprecatedNode()) || editingIgnoresContent(deprecatedNode()))
         return (atFirstEditingPositionForNode() || atLastEditingPositionForNode()) && !nodeIsUserSelectNone(deprecatedNode()->parentNode());
 
     if (isHTMLHtmlElement(*m_anchorNode))
         return false;
 
-    if (renderer->isRenderBlockFlow()) {
+    if (renderer->isRenderBlockFlow() || renderer->isFlexibleBox()) {

[Manuel Rego, 2015/02/10 22:31:37]

I think this is failing for grid too. Could you fix it?

I think you can use here !renderer->isRenderBlockFlow() to cover both cases.

Thanks!

[Manuel Rego, 2015/02/10 22:43:24]

Mmmm, I've just realized that this won't make any sense. I'm wondering if we
should just add isRenderGrid or if this "if" is actually needed for something
else.

Anyway, this is failing in grid too.

         if (toRenderBlock(renderer)->logicalHeight() || isHTMLBodyElement(*m_anchorNode)) {
             if (!Position::hasRenderedNonAnonymousDescendantsWithHeight(renderer))
                 return atFirstEditingPositionForNode() && !Position::nodeIsUserSelectNone(deprecatedNode());
             return m_anchorNode->hasEditableStyle() && !Position::nodeIsUserSelectNone(deprecatedNode()) && atEditingBoundary();
         }
     } else {
         LocalFrame* frame = m_anchorNode->document().frame();
         bool caretBrowsing = frame->settings() && frame->settings()->caretBrowsingEnabled();
         return (caretBrowsing || m_anchorNode->hasEditableStyle()) && !Position::nodeIsUserSelectNone(deprecatedNode()) && atEditingBoundary();
     }
@@ skipping 444 matching lines @@
     pos.showTreeForThis();
 }
 
 void showTree(const blink::Position* pos)
 {
     if (pos)
         pos->showTreeForThis();
 }
 
 #endif