LayoutTests/fast/forms/placeholder-content-center.html

<style>
input {
  -webkit-appearance: none;
  height: 40px;
  width: 600px;
  border: none;
  color: black;
  font-size: 10px;
}

::placeholder {
  color: black;
  font-size: 22px;
}
</style>
<input placeholder="PASS if placeholder text is fully visible">