MD Settings: Convert C++ handlers to be JavaScript-lifecycle aware.

chrome/browser/ui/webui/settings/settings_page_ui_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/settings_page_ui_handler.h"
 
 #include "content/public/browser/web_ui.h"
 
 namespace settings {
 
 SettingsPageUIHandler::SettingsPageUIHandler() {}
 
 SettingsPageUIHandler::~SettingsPageUIHandler() {}
 
 void SettingsPageUIHandler::ResolveJavascriptCallback(
     const base::Value& callback_id,
     const base::Value& response) {
   // cr.webUIResponse is a global JS function exposed from cr.js.
-  web_ui()->CallJavascriptFunction(
-      "cr.webUIResponse", callback_id,
-      base::FundamentalValue(true), response);
+  CallJavascriptFunction("cr.webUIResponse", callback_id,
+                         base::FundamentalValue(true), response);
 }
 
 void SettingsPageUIHandler::RejectJavascriptCallback(
     const base::Value& callback_id,
     const base::Value& response) {
   // cr.webUIResponse is a global JS function exposed from cr.js.
-  web_ui()->CallJavascriptFunction(
-      "cr.webUIResponse", callback_id,
-      base::FundamentalValue(false), response);
+  CallJavascriptFunction("cr.webUIResponse", callback_id,
+                         base::FundamentalValue(false), response);
 }
 
 }  // namespace settings