MD Settings: Remove usage of deprecated iron-flex-layout.html, for CrOS.

chrome/browser/resources/settings/internet_page/internet_page.html

 <link rel="import" href="chrome://resources/cr_elements/cr_expand_button/cr_expand_button.html">
 <link rel="import" href="chrome://resources/cr_elements/icons.html">
 <link rel="import" href="chrome://resources/cr_elements/network/cr_onc_types.html">
 <link rel="import" href="chrome://resources/html/i18n_behavior.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/neon-animation/neon-animatable.html">
 <link rel="import" href="chrome://resources/polymer/v1_0/paper-icon-button/paper-icon-button-light.html">
 <link rel="import" href="../prefs/prefs.html">
 <link rel="import" href="../route.html">
@@ skipping 12 matching lines @@
         -webkit-margin-end: 12px;
         -webkit-margin-start: 4px;
         height: 24px;
         width: 24px;
       }
     </style>
     <settings-animated-pages id="pages" section="internet"
         focus-config="[[focusConfig_]]">
       <neon-animatable route-path="default">
         <network-summary default-network="{{defaultNetwork}}"
-            device-states="{{deviceStates}}"            
+            device-states="{{deviceStates}}"
             networking-private="[[networkingPrivate]]">
         </network-summary>
         <template is="dom-if" if="[[allowAddConnection_(globalPolicy_)]]">
           <div actionable class="settings-box two-line"
               on-tap="onExpandAddConnectionsTap_">
             <div class="start layout horizontal center">
               <div>$i18n{internetAddConnection}</div>
             </div>
             <cr-expand-button alt="$i18n{internetAddConnectionExpandA11yLabel}"
                 id="expandAddConnections" expanded="{{addConnectionExpanded_}}">
@@ skipping 66 matching lines @@
               networking-private="[[networkingPrivate]]"
               show-spinner="{{showSpinner_}}">
           </settings-bluetooth-subpage>
         </settings-subpage>
       </template>
 
     </settings-animated-pages>
   </template>
   <script src="internet_page.js"></script>
 </dom-module>