MD Settings: Eliminate use of ES6 for Chrome OS

chrome/browser/resources/settings/internet_page/network_nameservers.js

Index: chrome/browser/resources/settings/internet_page/network_nameservers.js
diff --git a/chrome/browser/resources/settings/internet_page/network_nameservers.js b/chrome/browser/resources/settings/internet_page/network_nameservers.js
index 1dd03da514c1aa778e09d249e4dbd8282b62e725..98c592dc5549317ccd815e24e65eb51ab4b77595 100644
--- a/chrome/browser/resources/settings/internet_page/network_nameservers.js
+++ b/chrome/browser/resources/settings/internet_page/network_nameservers.js
@@ -110,7 +110,7 @@ Polymer({
   setNameservers_: function(nameserversType, nameservers) {
     if (nameserversType == 'custom') {
       // Add empty entries for unset custom nameservers.
-      for (let i = nameservers.length; i < this.MAX_NAMESERVERS; ++i)
+      for (var i = nameservers.length; i < this.MAX_NAMESERVERS; ++i)
         nameservers[i] = '';
     }
     this.nameservers_ = nameservers;
@@ -153,8 +153,8 @@ Polymer({
   onTypeChange_: function(event) {
     if (this.nameserversType_ == 'custom')
       this.savedNameservers_ = this.nameservers_;
-    let target = /** @type {!HTMLSelectElement} */ (event.target);
-    let type = target.value;
+    var target = /** @type {!HTMLSelectElement} */ (event.target);
+    var type = target.value;
     this.nameserversType_ = type;
     if (type == 'custom') {
       // Restore the saved nameservers.
@@ -187,11 +187,11 @@ Polymer({
     var type = this.nameserversType_;
 
     if (type == 'custom') {
-      let nameservers = [];
-      for (let i = 0; i < this.MAX_NAMESERVERS; ++i) {
-        let id = 'nameserver' + i;
-        let nameserverInput = this.$$('#' + id);
-        let nameserver = '';
+      var nameservers = [];

[dpapad, 2017/01/23 19:12:54]

Nit: You can use Array#map instead.

var nameservers = this.MAX_NAMESERVERS.map(function(i) {
  var nameserver = '';
  ...
  return nameserver;
}.bind(this));

[stevenjb, 2017/01/24 02:02:04]

MAX_NAMESERVERS is a number, not an Array. But I can pre-allocate the array and
greatly simplify this (very early JS) so I will do that.

+      for (var i = 0; i < this.MAX_NAMESERVERS; ++i) {
+        var id = 'nameserver' + i;
+        var nameserverInput = this.$$('#' + id);
+        var nameserver = '';
         if (nameserverInput)
           nameserver = this.$$('#' + id).value;
         nameservers.push(nameserver);
@@ -201,10 +201,9 @@ Polymer({
         value: nameservers,
       });
     } else if (type == 'google') {
-      let nameservers = this.GOOGLE_NAMESERVERS;
       this.fire('nameservers-change', {
         field: 'NameServers',
-        value: nameservers,
+        value: this.GOOGLE_NAMESERVERS,
       });
     } else {
       // automatic