MD Settings: convert paper-icon-button to paper-icon-button-light.

chrome/test/data/webui/settings/settings_subpage_test.js

Index: chrome/test/data/webui/settings/settings_subpage_test.js
diff --git a/chrome/test/data/webui/settings/settings_subpage_test.js b/chrome/test/data/webui/settings/settings_subpage_test.js
index 4b862b4cd838a2552210cbd12fec984081da0d12..343c7adabe093f828c7dc106dacdbd8160bc7033 100644
--- a/chrome/test/data/webui/settings/settings_subpage_test.js
+++ b/chrome/test/data/webui/settings/settings_subpage_test.js
@@ -16,7 +16,7 @@ cr.define('settings_subpage', function() {
       var subpage = document.createElement('settings-subpage');
       document.body.appendChild(subpage);
 
-      MockInteractions.tap(subpage.$$('paper-icon-button'));
+      MockInteractions.tap(subpage.$$('button'));
       assertEquals(settings.Route.PRIVACY, settings.getCurrentRoute());
     });
 
@@ -30,7 +30,7 @@ cr.define('settings_subpage', function() {
       var subpage = document.createElement('settings-subpage');
       document.body.appendChild(subpage);
 
-      MockInteractions.tap(subpage.$$('paper-icon-button'));
+      MockInteractions.tap(subpage.$$('button'));
 
       window.addEventListener('popstate', function(event) {
         assertEquals(settings.Route.BASIC, settings.getCurrentRoute());