MD Settings: Creating a <settings-dialog> element.

chrome/browser/resources/settings/on_startup_page/startup_urls_page.html

 <link rel="import" href="chrome://resources/polymer/v1_0/polymer/polymer.html">
-<link rel="import" href="chrome://resources/polymer/v1_0/paper-dialog/paper-dialog.html">
 <link rel="import" href="chrome://resources/polymer/v1_0/paper-input/paper-input.html">
-<link rel="import" href="chrome://md-settings/settings_dialog_css.html">
+<link rel="import" href="chrome://md-settings/settings_dialog.html">
 <link rel="import" href="chrome://md-settings/settings_shared_css.html">
 
 <dom-module id="settings-startup-urls-page">
   <link rel="import" type="css" href="on_startup_shared.css">
   <template>
     <style include="settings-dialog"></style>
     <style include="settings-shared"></style>
     <div class="list-frame vertical-list">
       <template is="dom-repeat" items="[[startupPages_]]">
         <div class="list-item">
           <iron-icon class="secondary" icon="image:brightness-1"
               item-icon></iron-icon>
           <div class="middle">
             <div class="text-elide">[[item.title]]</div>
             <div class="text-elide secondary">[[item.url]]</div>
           </div>
           <iron-icon on-tap="onRemoveUrlTap_" icon="clear"></iron-icon>
         </div>
       </template>
       <div class="list-item list-button" on-tap="onAddPageTap_"
           i18n-content="onStartupAddNewPage">
       </div>
       <div class="list-item list-button" on-tap="onUseCurrentPagesTap_"
           i18n-content="onStartupUseCurrent">
       </div>
     </div>
 
-    <paper-dialog modal id="addUrlDialog" class="layout vertical">
-      <div id="dialog-content">
-        <div class="top-row">
-          <div class="title" i18n-content="onStartupAddNewPage"></div>
-          <paper-icon-button icon="clear" on-tap="onCancelTap_" id="close">
-          </paper-icon-button>
-        </div>
-        <div class="body">
-          <div class="explanation">
-            <paper-input class="flex" always-float-label
-                i18n-values="label:onStartupSiteUrl" value="{{newUrl}}">
-            </paper-input>
-          </div>
-          <div class="button-container">
-            <div class="action-buttons">
-              <paper-button class="cancel-button" on-tap="onCancelTap_"
-                  id="cancel" i18n-content="cancel"></paper-button>
-              <!-- TODO(dbeam): this button should be [disabled] when |newUrl|
-                   is empty. -->
-              <paper-button class="action-button" on-tap="onOkTap_"
-                  id="addUrlButton" i18n-content="add"></paper-button>
-            </div>
-          </div>
+    <settings-dialog id="addUrlDialog">
+      <div class="title" i18n-content="onStartupAddNewPage"></div>
+      <div class="body">
+        <paper-input class="flex" always-float-label
+            i18n-values="label:onStartupSiteUrl" value="{{newUrl}}">
+        </paper-input>
+      </div>
+      <div class="button-container">
+        <div class="action-buttons">
+          <paper-button class="cancel-button" on-tap="onCancelTap_"
+              id="cancel" i18n-content="cancel"></paper-button>
+          <!-- TODO(dbeam): this button should be [disabled] when |newUrl|
+               is empty. -->
+          <paper-button class="action-button" on-tap="onOkTap_"
+              id="addUrlButton" i18n-content="add"></paper-button>
         </div>
       </div>
-    </paper-dialog>
-
+    </settings-dialog>
   </template>
   <script src="startup_urls_page.js"></script>
 </dom-module>