Tests that DOM.requestChildNodes respects depth parameter.
=== Get the Document ===
=== Get immediate children of the body ===
PASS: First child is a div
PASS: First child is div#depth-1
PASS: First child has one child
PASS: First child has no .children property
=== Get children of div#depth-1 three levels deep ===
PASS: div#depth-1 has nodes 3 levels deep
=== Get all children of body ===
PASS: div#depth-1 has nodes 9 levels deep
=== Pass an invalid depth ===
Backend error: Please provide a positive integer as a depth or -1 for entire subtree (-32000)