Demo UI made with a help of WUG toolkit (DO NOT SEND TO CQ).

chrome/browser/ui/webui/demo_ui/demo.cc

+// Copyright 2015 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/demo_ui/demo.h"
+
+#include "chrome/browser/profiles/profile.h"
+
+void Demo::Register() {
+  SetFactory(
+      [](content::BrowserContext* context) -> gen::DemoViewModel* {
+        return new Demo(Profile::FromBrowserContext(context));
+      });
+}
+
+Demo::Demo(Profile* profile) : profile_(profile) {
+}
+
+Demo::~Demo() {
+}
+
+void Demo::Initialize() {
+  GetContextEditor().SetString(kContextKeyUsername,
+                               profile_->GetProfileUserName());
+}