MD Settings: Display: Fix resolution text

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 140 matching lines @@
   /** @private */
   selectedDisplayChanged_: function() {
     // Set maxModeIndex first so that the slider updates correctly.
     if (this.selectedDisplay.modes.length == 0) {
       this.maxModeIndex_ = 0;
       this.selectedModeIndex_ = 0;
       return;
     }
     this.maxModeIndex_ = this.selectedDisplay.modes.length - 1;
     this.selectedModeIndex_ = this.getSelectedModeIndex_(this.selectedDisplay);
+    this.immediateSelectedModeIndex_ = this.selectedModeIndex_;
   },
 
   /**
    * @param {!Array<!chrome.system.display.DisplayUnitInfo>} displays
    * @return {boolean}
    * @private
    */
   showDisplayTabMenu_: function(displays) {
     return displays.length > 1;
   },
@@ skipping 65 matching lines @@
   /**
    * @param {!chrome.system.display.DisplayUnitInfo} selectedDisplay
    * @return {boolean}
    * @private
    */
   enableSetResolution_: function(selectedDisplay) {
     return selectedDisplay.modes.length > 1;
   },
 
   /**
-   * @param {!chrome.system.display.DisplayUnitInfo} selectedDisplay
-   * @param {number} immediateSelectedModeIndex
    * @return {string}
    * @private
    */
-  getResolutionText_: function(selectedDisplay, immediateSelectedModeIndex) {
+  getResolutionText_: function() {
     if (this.selectedDisplay.modes.length == 0) {
-      var widthStr = selectedDisplay.bounds.width.toString();
-      var heightStr = selectedDisplay.bounds.height.toString();
+      var widthStr = this.selectedDisplay.bounds.width.toString();
+      var heightStr = this.selectedDisplay.bounds.height.toString();
       return this.i18n('displayResolutionText', widthStr, heightStr);
     }
-    if (isNaN(immediateSelectedModeIndex))
-      immediateSelectedModeIndex = this.getSelectedModeIndex_(selectedDisplay);
-    var mode = selectedDisplay.modes[immediateSelectedModeIndex];
-    var best = selectedDisplay.isInternal ? mode.uiScale == 1.0 : mode.isNative;
+    // immediateSelectedModeIndex_ is bound to paper-slider.immediate-value
+    // which may not be valid, or may not have updated yet when this is called.
+    if (isNaN(this.immediateSelectedModeIndex_) ||
+        this.immediateSelectedModeIndex_ >= this.selectedDisplay.modes.length) {
+      this.immediateSelectedModeIndex_ =
+          this.getSelectedModeIndex_(this.selectedDisplay);
+    }
+    var mode = this.selectedDisplay.modes[this.immediateSelectedModeIndex_];
+    var best =
+        this.selectedDisplay.isInternal ? mode.uiScale == 1.0 : mode.isNative;
     var widthStr = mode.width.toString();
     var heightStr = mode.height.toString();
     if (best)
       return this.i18n('displayResolutionTextBest', widthStr, heightStr);
     else if (mode.isNative)
       return this.i18n('displayResolutionTextNative', widthStr, heightStr);
     return this.i18n('displayResolutionText', widthStr, heightStr);
   },
 
   /**
@@ skipping 122 matching lines @@
   },
 
   /** @private */
   setPropertiesCallback_: function() {
     if (chrome.runtime.lastError) {
       console.error(
           'setDisplayProperties Error: ' + chrome.runtime.lastError.message);
     }
   },
 });