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chromium/third_party/blink/web_tests/virtual/dark-color-scheme/date/date-picker-open.html 

<!DOCTYPE html>
<meta name="color-scheme" content="dark">
<script src="../../../resources/testdriver.js"></script>
<script src="../../../resources/testdriver-vendor.js"></script>
<script src="../../../fast/forms/resources/picker-common.js"></script>
<script src="../../../fast/forms/calendar-picker/resources/calendar-picker-common.js"></script>
  
<input type="date" value="2019-07-31">

<script>
  openPickerAppearanceOnly(document.querySelector('input'));
</script>