MD Settings: Use a browser proxy from the languages page. Re-enable test.

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

+// Copyright 2017 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 Fake implementation of chrome.inputMethodPrivate
+ * for testing.
+ */
+cr.define('settings', function() {
+  /**
+   * Fake of the chrome.inputMethodsPrivate API. Only methods that are called
+   * during testing have been implemented.
+   *
+   * @constructor
+   * @implements {InputMethodPrivate}
+   */
+  function FakeInputMethodPrivate() {}
+
+  FakeInputMethodPrivate.prototype = {
+    getCurrentInputMethod: function(callback) {
+      callback(null);
+    },
+
+    get onChanged() {
+      return {
+        addListener: function() {
+          // Nothing to do here.
+        },
+        removeListener: function() {
+          // Nothing to do here.
+        },
+      };
+    },
+  };
+
+  return {FakeInputMethodPrivate: FakeInputMethodPrivate};
+});