DOMUI Prefs: Change subpage close button to an actual button element

chrome/browser/resources/options.html

Index: chrome/browser/resources/options.html
diff --git a/chrome/browser/resources/options.html b/chrome/browser/resources/options.html
index eb6448ccd95f33e0bed7b3de91e0cde7284e9e17..95eb58f26d45b4316f740448eb3fd608dc248e60 100644
--- a/chrome/browser/resources/options.html
+++ b/chrome/browser/resources/options.html
@@ -337,8 +337,8 @@ window.onpopstate = function(e) {
        <!-- End main pages -->
        <div id="subpage-sheet-container" class="hidden">
          <div id="subpage-sheet">
-           <div class="close-subpage"
-               onclick="OptionsPage.closeSubPage();"></div>
+           <button class="close-subpage"
+               onclick="OptionsPage.closeSubPage();"></button>
            <if expr="pp_ifdef('chromeos')">
              <include src="options/about_page.html">
              <include src="options/chromeos_language_options.html">