MD Settings: add tests for mischievous default zoom handling

chrome/browser/resources/settings/appearance_page/appearance_browser_proxy.js

Index: chrome/browser/resources/settings/appearance_page/appearance_browser_proxy.js
diff --git a/chrome/browser/resources/settings/appearance_page/appearance_browser_proxy.js b/chrome/browser/resources/settings/appearance_page/appearance_browser_proxy.js
index e9cd6ec161be1bdf18aaf8a5e3c7591b72d16779..5f72e2798100c9328a28164bd87f431f2da776f8 100644
--- a/chrome/browser/resources/settings/appearance_page/appearance_browser_proxy.js
+++ b/chrome/browser/resources/settings/appearance_page/appearance_browser_proxy.js
@@ -7,6 +7,9 @@ cr.define('settings', function() {
   function AppearanceBrowserProxy() {}
 
   AppearanceBrowserProxy.prototype = {
+    /** @return {!Promise<number>} */
+    getDefaultZoom: assertNotReached,
+
     /**
      * @param {string} themeId
      * @return {!Promise<!chrome.management.ExtensionInfo>} Theme info.
@@ -37,6 +40,13 @@ cr.define('settings', function() {
 
   AppearanceBrowserProxyImpl.prototype = {
     /** @override */
+    getDefaultZoom: function() {
+      return new Promise(function(resolve) {
+        chrome.settingsPrivate.getDefaultZoom(resolve);
+      });
+    },
+
+    /** @override */
     getThemeInfo: function(themeId) {
       return new Promise(function(resolve) {
         chrome.management.get(themeId, resolve);