oobe-adaptive-dialog: use oobe-dialog-host shared style

Bug: 1151292
Change-Id: I104852ac093569248e1dc0ba5c04e728493f42d9
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2623548Reviewed-by: Denis Kuznetsov [CET] <antrim@chromium.org>
Reviewed-by: Roman Aleksandrov <raleksandrov@google.com>
Commit-Queue: Yunke Zhou <yunkez@google.com>
Cr-Commit-Position: refs/heads/master@{#842512}

chrome/browser/resources/chromeos/login/components/oobe_adaptive_dialog/oobe_adaptive_dialog_old.html

@@ -17,6 +17,7 @@
 -->
 <dom-module id="oobe-adaptive-dialog">
   <template>
+    <style include="oobe-dialog-host"></style>
     <oobe-dialog id="dialog" has-buttons hide-shadow$="[[hideShadow]]"
         no-lazy$="[[noLazy]]" no-header$="[[noHeader]]"
         no-footer-padding$="[[noFooterPadding]]"
@@ -32,4 +33,3 @@
   </template>
   <script src="oobe_adaptive_dialog.js"></script>
 </dom-module>
-

chrome/browser/resources/chromeos/login/components/oobe_adaptive_dialog/oobe_adaptive_dialog_old.js

@@ -66,7 +66,7 @@ Polymer({
    * This is called from oobe_welcome when this dialog is shown.
    */
   show() {
-    this.$.show();
+    this.$.dialog.show();
   },
 
 });