third_party/WebKit/LayoutTests/editing/deleting/pruning-after-merge-1.html

<script>
if (window.testRunner) {
     testRunner.dumpEditingCallbacks();
     testRunner.dumpAsText();
}
</script>
<p>This tests the pruning that delete does when the it merges two paragraphs when the selection to delete spans multiple blocks.</p>
<p>You should see:<br>b<b>ar<br>baz</b></p>
<div id="test" contenteditable="true">boo<b><div>bar</div><div>baz</div></b></div>

<script>
var s = window.getSelection();
var e = document.getElementById("test");

s.collapse(e, 0);
s.modify("move", "forward", "character");
s.modify("extend", "forward", "line");

document.execCommand("Delete");
</script>