[ContentEditable] List creation is broken on specific situation

[Frederico Caldeira Knabben]

1. Load the following HTML:

<p>Para 1</p>
<p><span contenteditable="false">Non Editable</span></p>
<p>Para 2</p>

2. Hit CTRL+A to select all.

3. Click the list button.

Current results:

All contents get lost and a js error is thrown.

Expected results:

All paragraphs (including the one with the read only content) should form a single list.

This one is related to the ​contenteditable feature branch.

[Frederico Caldeira Knabben]

WFM now.