MD Settings: Use FireWebUIListener() helper wherever possible.

chrome/browser/ui/webui/settings/chromeos/device_pointer_handler.cc

 // 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.
 
 #include "chrome/browser/ui/webui/settings/chromeos/device_pointer_handler.h"
 
 #include "base/bind.h"
 #include "base/values.h"
 #include "content/public/browser/web_ui.h"
 
@@ skipping 18 matching lines @@
 
   pointer_device_observer_->AddObserver(this);
   pointer_device_observer_->CheckDevices();
 }
 
 void PointerHandler::OnJavascriptDisallowed() {
   pointer_device_observer_->RemoveObserver(this);
 }
 
 void PointerHandler::TouchpadExists(bool exists) {
-  CallJavascriptFunction("cr.webUIListenerCallback",
-                         base::Value("has-touchpad-changed"),
-                         base::Value(exists));
+  FireWebUIListener("has-touchpad-changed", base::Value(exists));
 }
 
 void PointerHandler::MouseExists(bool exists) {
-  CallJavascriptFunction("cr.webUIListenerCallback",
-                         base::Value("has-mouse-changed"), base::Value(exists));
+  FireWebUIListener("has-mouse-changed", base::Value(exists));
 }
 
 void PointerHandler::HandleInitialize(const base::ListValue* args) {
   AllowJavascript();
 }
 
 }  // namespace settings
 }  // namespace chromeos