Fix MD display settings when the display supports a single resolution

chrome/browser/resources/settings/controls/settings_slider.js

Index: chrome/browser/resources/settings/controls/settings_slider.js
diff --git a/chrome/browser/resources/settings/controls/settings_slider.js b/chrome/browser/resources/settings/controls/settings_slider.js
index c6b9b59e007198601fa4935a3b07ec8cdf929234..4d7c9e4f785e9ec1302f22d4a6fe3e196e464e74 100644
--- a/chrome/browser/resources/settings/controls/settings_slider.js
+++ b/chrome/browser/resources/settings/controls/settings_slider.js
@@ -50,11 +50,16 @@ Polymer({
    * @private
    */
   onSliderChanged_: function() {
+    var sliderValue =
+      (this.$.slider.immediateValue && this.$.slider.immediateValue != NaN)

[stevenjb, 2017/04/19 19:24:16]

immediateValue == 0 should be valid, check explicitly for === undefined instead.

[afakhry, 2017/04/19 20:08:23]

Done. 
Also, I asked xiyuan, and he told me that the right way to check for NaN is to
call isNaN():
https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Obje...

So I modified that too. Please take a look.

+        ? this.$.slider.immediateValue
+        : this.$.slider.value;
+
     var newValue;
     if (this.tickValues && this.tickValues.length > 0)
-      newValue = this.tickValues[this.$.slider.immediateValue];
+      newValue = this.tickValues[sliderValue];
     else
-      newValue = this.$.slider.immediateValue;
+      newValue = sliderValue;
 
     this.set('pref.value', newValue);
   },