<!DOCTYPE HTML> <iframe id="frame" srcdoc="<style>input { width: 100px; }</style><input id='input' value='add stuff here'></input>"></iframe> <script> if (window.testRunner) testRunner.dumpAsText(); if (window.internals) window.internals.settings.setPreferCompositingToLCDTextEnabled(true); onload = function() { var layerTreePreStyleUpdate = ""; var layerTreePostStyleUpdate = ""; document.getElementById("frame").contentDocument.getElementById("input").value = "This is a very long string that will cause overflow"; layerTreePreStyleUpdate = window.internals.layerTreeAsText(document); // Force a style recalc. document.body.offsetTop; layerTreePostStyleUpdate = window.internals.layerTreeAsText(document); var pre = document.createElement('pre'); if (layerTreePreStyleUpdate === layerTreePostStyleUpdate) pre.innerHTML = "PASS - layer trees are the same."; else pre.innerHTML = "FAIL - layer trees are not the same."; document.body.appendChild(pre); }; </script>