Enable user change background image in settings page in Aura build.

chrome/browser/resources/options2/browser_options.js

Index: chrome/browser/resources/options2/browser_options.js
diff --git a/chrome/browser/resources/options2/browser_options.js b/chrome/browser/resources/options2/browser_options.js
index 7d395f3f63c80513e628a0154f81ed67065ec1eb..68e801201dbee7e8bbb02895c6b79e05337ae917 100644
--- a/chrome/browser/resources/options2/browser_options.js
+++ b/chrome/browser/resources/options2/browser_options.js
@@ -107,6 +107,12 @@ cr.define('options', function() {
             self.onHomePagePrefChanged_.bind(self));
       });
 
+      if ($('set-wallpaper')) {
+        $('set-wallpaper').onclick = function(event) {
+          OptionsPage.navigateToPage('setWallpaper');
+        };
+      }
+
       $('themes-gallery').onclick = function(event) {
         window.open(localStrings.getString('themesGalleryURL'));
       };