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

chrome/browser/ui/webui/demo_ui/strings/strings_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/strings/strings_demo.h"
+
+#include "base/bind.h"
+#include "base/bind_helpers.h"
+#include "base/strings/stringprintf.h"
+#include "base/time/time.h"
+#include "base/timer/timer.h"
+
+StringsDemo::StringsDemo() : timer_(true, true) {
+}
+
+StringsDemo::~StringsDemo() {
+}
+
+void StringsDemo::Register() {
+  SetFactory(
+      [](content::BrowserContext*)
+          -> gen::StringsDemoViewModel* { return new StringsDemo(); });
+}
+
+void StringsDemo::Initialize() {
+  timer_.Start(FROM_HERE, base::TimeDelta::FromSeconds(1),
+               base::Bind(&StringsDemo::UpdateClock, base::Unretained(this)));
+}
+
+void StringsDemo::UpdateClock() {
+  base::Time::Exploded now;
+  base::Time::Now().LocalExplode(&now);
+  GetContextEditor()
+      .SetString(kContextKeyHours, base::StringPrintf("%02d", now.hour))
+      .SetString(kContextKeyMinutes, base::StringPrintf("%02d", now.minute))
+      .SetString(kContextKeySeconds, base::StringPrintf("%02d", now.second));
+}