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

chrome/browser/resources/settings/device_page/display.html

 <link rel="import" href="chrome://resources/html/polymer.html">
 <link rel="import" href="chrome://resources/html/i18n_behavior.html">
 <link rel="import" href="chrome://resources/html/md_select_css.html">
-<link rel="import" href="chrome://resources/polymer/v1_0/iron-flex-layout/classes/iron-flex-layout.html">
+<link rel="import" href="chrome://resources/polymer/v1_0/iron-flex-layout/iron-flex-layout-classes.html">
 <link rel="import" href="chrome://resources/polymer/v1_0/paper-button/paper-button.html">
 <link rel="import" href="chrome://resources/polymer/v1_0/paper-icon-button/paper-icon-button-light.html">
 <link rel="import" href="chrome://resources/polymer/v1_0/paper-tabs/paper-tabs.html">
 <link rel="import" href="chrome://resources/polymer/v1_0/paper-toggle-button/paper-toggle-button.html">
 <link rel="import" href="display_layout.html">
 <link rel="import" href="display_overscan_dialog.html">
 <link rel="import" href="../controls/settings_slider.html">
 <link rel="import" href="../settings_shared_css.html">
 <link rel="import" href="../settings_vars_css.html">
 
 <dom-module id="settings-display">
   <template>
-    <style include="settings-shared md-select">
+    <style include="settings-shared md-select iron-flex iron-flex-alignment">
      .settings-box.embedded {
        -webkit-margin-start: 20px;
        align-self: stretch;
        padding: 0;
      }
 
      :host {
        --paper-tabs-selection-bar-color: var(--paper-blue-500);
      }
 
@@ skipping 15 matching lines @@
      .settings-box > paper-button:first-child {
        -webkit-padding-start: 0
      }
 
      paper-tab {
        text-transform: uppercase;
      }
 
      #controlsDiv > .settings-box:first-of-type {
        border-top: none;
-     } 
+     }
     </style>
     <div class="settings-box first layout vertical self-stretch">
       <h2 class="layout self-start">
         $i18n{displayArrangementTitle}
       </h2>
       <div class="secondary layout self-start"
           hidden="[[!hasMultipleDisplays_(displays)]]">
         $i18n{displayArrangementText}
       </div>
       <display-layout id="displayLayout"
@@ skipping 128 matching lines @@
           </div>
         </div>
         <button class="subpage-arrow" is="paper-icon-button-light"
             aria-label="$i18n{displayTouchCalibrationTitle}"
             aria-describedby="touchCalibrationSecondary"></button>
       </div>
     </div>
   </template>
   <script src="display.js"></script>
 </dom-module>