cros: Use runtime stylus detection for ash palette.

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

 // Copyright 2017 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_stylus_handler.h"
 
+#include "ash/common/system/chromeos/palette/palette_utils.h"
+#include "base/bind.h"
 #include "chrome/browser/profiles/profile.h"
+#include "ui/events/devices/input_device_manager.h"
 
 namespace chromeos {
 namespace settings {
 
 namespace {
 
 // Keys in objects passed to onNoteTakingAppsUpdated.
 constexpr char kAppNameKey[] = "name";
 constexpr char kAppIdKey[] = "value";
 constexpr char kAppPreferredKey[] = "preferred";
 
 }  // namespace
 
 StylusHandler::StylusHandler() {
   NoteTakingHelper::Get()->AddObserver(this);
+  ui::InputDeviceManager::GetInstance()->AddObserver(this);
 }
 
 StylusHandler::~StylusHandler() {
+  ui::InputDeviceManager::GetInstance()->RemoveObserver(this);
   NoteTakingHelper::Get()->RemoveObserver(this);
 }
 
 void StylusHandler::RegisterMessages() {
   DCHECK(web_ui());
 
   web_ui()->RegisterMessageCallback(
+      "initializeStylusSettings",
+      base::Bind(&StylusHandler::HandleInitialize, base::Unretained(this)));
+  web_ui()->RegisterMessageCallback(
       "requestNoteTakingApps",
       base::Bind(&StylusHandler::RequestApps, base::Unretained(this)));
   web_ui()->RegisterMessageCallback(
       "setPreferredNoteTakingApp",
       base::Bind(&StylusHandler::SetPreferredNoteTakingApp,
                  base::Unretained(this)));
 }
 
 void StylusHandler::OnAvailableNoteTakingAppsUpdated() {
   UpdateNoteTakingApps();
 }
 
+void StylusHandler::OnDeviceListsComplete() {
+  SendHasStylus();
+}
+
 void StylusHandler::UpdateNoteTakingApps() {
   bool waiting_for_android = false;
   note_taking_app_ids_.clear();
   base::ListValue apps_list;
 
   NoteTakingHelper* helper = NoteTakingHelper::Get();
   if (helper->android_enabled() && !helper->android_apps_received()) {
     // If Android is enabled but not ready yet, let the JS know so it can
     // disable the menu and display an explanatory message.
     waiting_for_android = true;
@@ skipping 29 matching lines @@
   // currently-available set.
   if (!note_taking_app_ids_.count(app_id)) {
     LOG(ERROR) << "Got unknown note-taking-app ID \"" << app_id << "\"";
     return;
   }
 
   NoteTakingHelper::Get()->SetPreferredApp(Profile::FromWebUI(web_ui()),
                                            app_id);
 }
 
+void StylusHandler::HandleInitialize(const base::ListValue* args) {
+  AllowJavascript();
+  if (ui::InputDeviceManager::GetInstance()->AreDeviceListsComplete())
+    SendHasStylus();
+}
+
+void StylusHandler::SendHasStylus() {
+  DCHECK(ui::InputDeviceManager::GetInstance()->AreDeviceListsComplete());
+  CallJavascriptFunction(
+      "cr.webUIListenerCallback", base::StringValue("has-stylus-changed"),
+      base::FundamentalValue(ash::palette_utils::HasStylusInput()));
+}
+
 }  // namespace settings
 }  // namespace chromeos