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

chrome/browser/resources/settings/people_page/import_data_browser_proxy.js

 // Copyright 2016 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 /**
  * @fileoverview A helper object used from the the Import Data dialog to allow
  * users to import data (like bookmarks) from other web browsers.
  */
 cr.exportPath('settings');
 
@@ skipping 18 matching lines @@
  */
 settings.ImportDataStatus = {
   INITIAL: 'initial',
   IN_PROGRESS: 'inProgress',
   SUCCEEDED: 'succeeded',
   FAILED: 'failed',
 };
 
 cr.define('settings', function() {
   /** @interface */
-  function ImportDataBrowserProxy() {}
-
-  ImportDataBrowserProxy.prototype = {
+  class ImportDataBrowserProxy {
     /**
      * Returns the source profiles available for importing from other browsers.
      * @return {!Promise<!Array<!settings.BrowserProfile>>}
      */
-    initializeImportDialog: function() {},
+    initializeImportDialog() {}
 
     /**
      * Starts importing data for the specificed source browser profile. The C++
      * responds with the 'import-data-status-changed' WebUIListener event.
      * @param {number} sourceBrowserProfileIndex
      */
-    importData: function(sourceBrowserProfileIndex) {},
+    importData(sourceBrowserProfileIndex) {}
 
     /**
      * Prompts the user to choose a bookmarks file to import bookmarks from.
      */
-    importFromBookmarksFile: function() {},
-  };
+    importFromBookmarksFile() {}
+  }
 
   /**
-   * @constructor
    * @implements {settings.ImportDataBrowserProxy}
    */
-  function ImportDataBrowserProxyImpl() {}
+  class ImportDataBrowserProxyImpl {
+    /** @override */
+    initializeImportDialog() {
+      return cr.sendWithPromise('initializeImportDialog');
+    }
+
+    /** @override */
+    importData(sourceBrowserProfileIndex) {
+      chrome.send('importData', [sourceBrowserProfileIndex]);
+    }
+
+    /** @override */
+    importFromBookmarksFile() {
+      chrome.send('importFromBookmarksFile');
+    }
+  }
+
   // The singleton instance_ is replaced with a test version of this wrapper
   // during testing.
   cr.addSingletonGetter(ImportDataBrowserProxyImpl);
 
-  ImportDataBrowserProxyImpl.prototype = {
-    /** @override */
-    initializeImportDialog: function() {
-      return cr.sendWithPromise('initializeImportDialog');
-    },
-
-    /** @override */
-    importData: function(sourceBrowserProfileIndex) {
-      chrome.send('importData', [sourceBrowserProfileIndex]);
-    },
-
-    /** @override */
-    importFromBookmarksFile: function() {
-      chrome.send('importFromBookmarksFile');
-    },
-  };
-
   return {
     ImportDataBrowserProxy: ImportDataBrowserProxy,
     ImportDataBrowserProxyImpl: ImportDataBrowserProxyImpl,
   };
 });