MD Settings: First half of Device > Keyboard sub-page.

chrome/browser/ui/webui/settings/chromeos/device_keyboard_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_keyboard_handler.h"
+
+#include "base/bind.h"
+#include "base/command_line.h"
+#include "base/values.h"
+#include "chrome/browser/profiles/profile.h"
+#include "chromeos/chromeos_switches.h"
+#include "content/public/browser/web_ui.h"
+#include "ui/events/devices/device_data_manager.h"
+#include "ui/events/devices/keyboard_device.h"
+
+namespace {
+
+bool HasExternalKeyboard() {
+  for (const ui::KeyboardDevice& keyboard :
+       ui::DeviceDataManager::GetInstance()->keyboard_devices()) {
+    if (keyboard.type == ui::InputDeviceType::INPUT_DEVICE_EXTERNAL)
+      return true;
+  }
+
+  return false;
+}
+
+}  // namespace
+
+namespace chromeos {
+namespace settings {
+
+KeyboardHandler::KeyboardHandler(content::WebUI* webui)
+    : profile_(Profile::FromWebUI(webui)) {
+  ui::DeviceDataManager::GetInstance()->AddObserver(this);
+}
+
+KeyboardHandler::~KeyboardHandler() {
+  ui::DeviceDataManager::GetInstance()->RemoveObserver(this);
+}
+
+void KeyboardHandler::RegisterMessages() {
+  web_ui()->RegisterMessageCallback(
+      "initializeKeyboardSettings",
+      base::Bind(&KeyboardHandler::HandleInitialize,
+                 base::Unretained(this)));
+}
+
+void KeyboardHandler::OnKeyboardDeviceConfigurationChanged() {
+  UpdateShowKeys();
+}
+
+void KeyboardHandler::HandleInitialize(const base::ListValue* args) {
+  UpdateShowKeys();
+}
+
+void KeyboardHandler::UpdateShowKeys() const {
+  const base::FundamentalValue has_caps_lock(HasExternalKeyboard());
+  const base::FundamentalValue has_diamond_key(
+      base::CommandLine::ForCurrentProcess()->HasSwitch(
+          chromeos::switches::kHasChromeOSDiamondKey));
+  web_ui()->CallJavascriptFunction("cr.webUIListenerCallback",
+                                   base::StringValue("show-keys-changed"),
+                                   has_caps_lock,
+                                   has_diamond_key);
+}
+
+}  // namespace settings
+}  // namespace chromeos