MD Settings: Convert all browser proxies to use ES6 class syntax.

chrome/browser/resources/settings/system_page/system_page_browser_proxy.js

Index: chrome/browser/resources/settings/system_page/system_page_browser_proxy.js
diff --git a/chrome/browser/resources/settings/system_page/system_page_browser_proxy.js b/chrome/browser/resources/settings/system_page/system_page_browser_proxy.js
index b9ac51b3328fa7d63d6b4e65a4e69f9e041e4312..3b4d509bc4b4f2af710a854c712388d762bb87c2 100644
--- a/chrome/browser/resources/settings/system_page/system_page_browser_proxy.js
+++ b/chrome/browser/resources/settings/system_page/system_page_browser_proxy.js
@@ -6,38 +6,33 @@
 
 cr.define('settings', function() {
   /** @interface */
-  function SystemPageBrowserProxy() {}
-
-  SystemPageBrowserProxy.prototype = {
+  class SystemPageBrowserProxy {
     /** Shows the native system proxy settings. */
-    showProxySettings: function() {},
+    showProxySettings() {}
 
     /**
      * @return {boolean} Whether hardware acceleration was enabled when the user
      *     started Chrome.
      */
-    wasHardwareAccelerationEnabledAtStartup: function() {},
-  };
+    wasHardwareAccelerationEnabledAtStartup() {}
+  }
 
   /**
-   * @constructor
    * @implements {settings.SystemPageBrowserProxy}
    */
-  function SystemPageBrowserProxyImpl() {}
-
-  cr.addSingletonGetter(SystemPageBrowserProxyImpl);
-
-  SystemPageBrowserProxyImpl.prototype = {
+  class SystemPageBrowserProxyImpl {
     /** @override */
-    showProxySettings: function() {
+    showProxySettings() {
       chrome.send('showProxySettings');
-    },
+    }
 
     /** @override */
-    wasHardwareAccelerationEnabledAtStartup: function() {
+    wasHardwareAccelerationEnabledAtStartup() {
       return loadTimeData.getBoolean('hardwareAccelerationEnabledAtStartup');
-    },
-  };
+    }
+  }
+
+  cr.addSingletonGetter(SystemPageBrowserProxyImpl);
 
   return {
     SystemPageBrowserProxy: SystemPageBrowserProxy,