chrome/browser/resources/chromeos/first_run/greeting_step.html

<div id="greeting" class="step dialog">
  <div class="topbutton-bar">
    <div class="topbutton-wrapper">
      <button class="custom-appearance close-button"></button>
    </div>
  </div>
  <h1 i18n-content="greetingHeader"></h1>
  <p>
    <span i18n-content="greetingText1"></span><br>
    <span i18n-content="greetingText2"></span>
  </p>
  <div class="controls">
    <button i18n-content="greetingButton"
        class="next-button custom-appearance blue-button"></button>
  </div>
  <include src="greeting_image_[GREETING_IMAGE].html">
</div>