MD Settings: Fix styles in several places.

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

Index: chrome/browser/resources/settings/controls/controlled_button.js
diff --git a/chrome/browser/resources/settings/controls/controlled_button.js b/chrome/browser/resources/settings/controls/controlled_button.js
index d1b97231b589064ca4a4d9aa74c0da9445c3a6aa..f04f927c67fff6fbec5d917f33be7c7f60390e96 100644
--- a/chrome/browser/resources/settings/controls/controlled_button.js
+++ b/chrome/browser/resources/settings/controls/controlled_button.js
@@ -18,6 +18,12 @@ Polymer({
       reflectToAttribute: true,
     },
 
+    iconClass: {
+      type: String,
+      value: null,
+      reflectToAttribute: true,
+    },
+
     /** @private */
     controlled_: {
       type: Boolean,