Make update over cellular an option for user

chrome/browser/resources/settings/about_page/about_page.html

 <link rel="import" href="chrome://resources/html/polymer.html">
 <link rel="import" href="about_page_browser_proxy.html">
 <link rel="import" href="../i18n_setup.html">
 <link rel="import" href="../icons.html">
 <link rel="import" href="../lifetime_browser_proxy.html">
 <link rel="import" href="../route.html">
 <link rel="import" href="../settings_page/main_page_behavior.html">
 <link rel="import" href="../settings_page/settings_animated_pages.html">
 <link rel="import" href="../settings_page/settings_section.html">
 <link rel="import" href="../settings_page_css.html">
 <link rel="import" href="../settings_shared_css.html">
 <link rel="import" href="chrome://resources/cr_elements/icons.html">
 <link rel="import" href="chrome://resources/html/assert.html">
 <link rel="import" href="chrome://resources/html/i18n_behavior.html">
 <link rel="import" href="chrome://resources/html/web_ui_listener_behavior.html">
 <link rel="import" href="chrome://resources/polymer/v1_0/iron-icon/iron-icon.html">
 <link rel="import" href="chrome://resources/polymer/v1_0/neon-animation/neon-animatable.html">
 <link rel="import" href="chrome://resources/polymer/v1_0/paper-button/paper-button.html">
 
 <if expr="chromeos">
 <link rel="import" href="detailed_build_info.html">
+<link rel="import" href="update_warning_dialog.html">
 <link rel="import" href="../settings_page/settings_subpage.html">
 </if>
 
 <if expr="_google_chrome and is_macosx">
 <link rel="import" href="chrome://resources/polymer/v1_0/paper-icon-button/paper-icon-button-light.html">
 </if>
 
 <dom-module id="settings-about-page">
   <template>
     <style include="settings-shared settings-page-styles">
@@ skipping 183 matching lines @@
 <if expr="chromeos">
           <template is="dom-if" route-path="/help/details">
             <settings-subpage page-title="$i18n{aboutDetailedBuildInfo}">
               <settings-detailed-build-info></settings-detailed-build-info>
             </settings-subpage>
           </template>
 </if>
         </settings-animated-pages>
       </settings-section>
     </div>
+<if expr="chromeos">
+    <template is="dom-if" if="[[showUpdateWarningDialog_]]" restamp>
+      <settings-update-warning-dialog update-info="[[updateInfo_]]"
+          on-close="onUpdateWarningDialogClose_">
+      </settings-update-warning-dialog>
+    </template>
+</if>
   </template>
   <script src="about_page.js"></script>
 </dom-module>