ChromeOS OOBE: fix focus flow in MD-OOBE.

chrome/browser/resources/chromeos/login/oobe_eula.html

Index: chrome/browser/resources/chromeos/login/oobe_eula.html
diff --git a/chrome/browser/resources/chromeos/login/oobe_eula.html b/chrome/browser/resources/chromeos/login/oobe_eula.html
index 013c863f40ae72bca343d4c9e157ec3d028ead50..12958f59e50ea6e00e9588339f169c72993f6dce 100644
--- a/chrome/browser/resources/chromeos/login/oobe_eula.html
+++ b/chrome/browser/resources/chromeos/login/oobe_eula.html
@@ -27,21 +27,25 @@
   <template>
     <link rel="stylesheet" href="oobe_eula.css">
     <link rel="stylesheet" href="oobe_dialog_parameters.css">
-    <oobe-dialog hidden="[[!eulaLoadingScreenShown]]"
+    <oobe-dialog id="eulaLoadingDialog" hidden="[[!eulaLoadingScreenShown]]"
+        role="dialog" aria-label="$i18n{termsOfServiceLoading}"
         has-buttons>
       <iron-icon icon="oobe-eula:googleg" class="oobe-icon"></iron-icon>
       <div class="header">
         <h1 class="title" i18n-content="termsOfServiceLoading"></h1>
       </div>
     </oobe-dialog>
-    <oobe-dialog hidden="[[!eulaScreenShown]]"
+    <oobe-dialog id="eulaDialog" hidden="[[eulaLoadingScreenShown]]"
+        role="dialog" aria-label="$i18n{oobeEulaSectionTitle}"
         has-buttons>
       <iron-icon icon="oobe-eula:googleg" class="oobe-icon"></iron-icon>
       <div class="header">
         <h1 class="title" i18n-content="oobeEulaSectionTitle"></h1>
       </div>
       <div class="footer flex layout vertical">
-        <iframe id="crosEulaFrame" class="flex" src="chrome://terms"
+        <iframe id="crosEulaFrame" src="chrome://terms"
+            role="document" class="flex focus-on-show"
+            aria-label="$i18n{oobeEulaIframeLabel}"
             on-load="onFrameLoad_">
         </iframe>
         <a id="installationSettings" href="#"