[MD settings] one way binding for side nav arrow icons

chrome/browser/resources/settings/settings_menu/settings_menu.html

 <link rel="import" href="chrome://resources/html/polymer.html">
 <link rel="import" href="chrome://resources/polymer/v1_0/iron-icon/iron-icon.html">
 <link rel="import" href="chrome://resources/polymer/v1_0/iron-icons/av-icons.html">
 <link rel="import" href="chrome://resources/polymer/v1_0/iron-icons/device-icons.html">
 <link rel="import" href="chrome://resources/polymer/v1_0/iron-icons/hardware-icons.html">
 <link rel="import" href="chrome://resources/polymer/v1_0/iron-icons/image-icons.html">
 <link rel="import" href="chrome://resources/polymer/v1_0/iron-icons/iron-icons.html">
 <link rel="import" href="chrome://resources/polymer/v1_0/iron-icons/social-icons.html">
 <link rel="import" href="chrome://resources/polymer/v1_0/paper-menu/paper-menu.html">
 <link rel="import" href="chrome://resources/polymer/v1_0/paper-menu/paper-submenu.html">
@@ skipping 53 matching lines @@
         font-size: 13px;
         font-weight: 500;
         min-height: 40px;
       }
     </style>
     <paper-menu name="root-menu">
       <paper-submenu opened="{{basicOpened_}}">
         <div class="menu-trigger" data-page="basic" data-section=""
             on-tap="openPage_">
           <span i18n-content="basicPageTitle"></span>
-          <iron-icon icon="{{arrowState_(basicOpened_)}}" item-icon></iron-icon>
+          <iron-icon icon="[[arrowState_(basicOpened_)]]" item-icon></iron-icon>
         </div>
         <paper-menu class="menu-content">
 <if expr="chromeos">
           <div data-page="basic" data-section="internet" on-tap="openPage_">
             <iron-icon icon="device:network-wifi" item-icon></iron-icon>
             <span i18n-content="internetPageTitle"></span>
           </div>
 </if>
           <div data-page="basic" data-section="people" on-tap="openPage_">
             <iron-icon icon="social:people" item-icon></iron-icon>
@@ skipping 23 matching lines @@
           <div data-page="basic" data-section="onStartup" on-tap="openPage_">
             <iron-icon icon="icons:power-settings-new" item-icon></iron-icon>
             <span i18n-content="onStartup"></span>
           </div>
         </paper-menu>
       </paper-submenu>
       <paper-submenu opened="{{advancedOpened_}}">
         <div class="menu-trigger" data-page="advanced" data-section=""
             on-tap="openPage_">
           <span i18n-content="advancedPageTitle"></span>
-          <iron-icon icon="{{arrowState_(advancedOpened_)}}" item-icon>
+          <iron-icon icon="[[arrowState_(advancedOpened_)]]" item-icon>
           </iron-icon>
         </div>
         <paper-menu class="menu-content">
 <if expr="chromeos">
           <div data-page="advanced" data-section="dateTime" on-tap="openPage_">
             <iron-icon icon="device:access-time" item-icon></iron-icon>
             <span i18n-content="dateTimePageTitle"></span>
           </div>
 </if>
           <div data-page="advanced" data-section="privacy" on-tap="openPage_">
@@ skipping 37 matching lines @@
       </paper-submenu>
       <paper-submenu on-tap="openPage_">
         <div class="menu-trigger">
           <span i18n-content="aboutProgram"></span>
         </div>
       </paper-submenu>
     </paper-menu>
   </template>
   <script src="settings_menu.js"></script>
 </dom-module>