MD Settings: Display: Fix selected display update

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

 // Copyright 2016 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 /**
  * @fileoverview
  * 'settings-display' is the settings subpage for display settings.
  */
 
 cr.define('settings.display', function() {
@@ skipping 278 matching lines @@
   /**
    * @param {!{detail: string}} e |e.detail| is the id of the selected display.
    * @private
    */
   onSelectDisplay_: function(e) {
     var id = e.detail;
     for (var i = 0; i < this.displays.length; ++i) {
       var display = this.displays[i];
       if (id != display.id)
         continue;
-      this.currentSelectedModeIndex_ = -1;
-      this.selectedDisplay = display;
+      if (this.selectedDisplay != display) {
+        // Set currentSelectedModeIndex_ to -1 so that getResolutionText_ does
+        // not flicker. selectedDisplayChanged will update selectedModeIndex_
+        // and currentSelectedModeIndex_ correctly.
+        this.currentSelectedModeIndex_ = -1;
+        this.selectedDisplay = display;
+      }
     }
   },
 
   /**
    * Handles event when a display tab is selected.
    * @param {!{detail: !{item: !{displayId: string}}}} e
    * @private
    */
   onSelectDisplayTab_: function(e) {
     this.onSelectDisplay_({detail: e.detail.item.displayId});
@@ skipping 126 matching lines @@
   },
 
   /** @private */
   setPropertiesCallback_: function() {
     if (chrome.runtime.lastError) {
       console.error(
           'setDisplayProperties Error: ' + chrome.runtime.lastError.message);
     }
   },
 });