Sync ui/events to chromium @ https://codereview.chromium.org/1210203002

ui/events/devices/x11/device_list_cache_x11.cc

+// Copyright (c) 2012 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 "ui/events/devices/x11/device_list_cache_x11.h"
+
+#include <algorithm>
+
+#include "base/memory/singleton.h"
+#include "base/message_loop/message_loop.h"
+#include "ui/events/devices/x11/device_data_manager_x11.h"
+
+namespace {
+
+bool IsXI2Available() {
+#if defined(USE_AURA)
+  return ui::DeviceDataManagerX11::GetInstance()->IsXInput2Available();
+#else
+  return false;
+#endif
+}
+
+}
+
+namespace ui {
+
+DeviceListCacheX11::DeviceListCacheX11() {
+}
+
+DeviceListCacheX11::~DeviceListCacheX11() {
+}
+
+DeviceListCacheX11* DeviceListCacheX11::GetInstance() {
+  return Singleton<DeviceListCacheX11>::get();
+}
+
+void DeviceListCacheX11::UpdateDeviceList(Display* display) {
+  XDeviceList& new_x_dev_list = x_dev_list_;
+  new_x_dev_list.devices.reset(
+      XListInputDevices(display, &new_x_dev_list.count));
+
+  XIDeviceList& new_xi_dev_list = xi_dev_list_;
+  new_xi_dev_list.devices.reset(
+      IsXI2Available()
+          ? XIQueryDevice(display, XIAllDevices, &new_xi_dev_list.count)
+          : nullptr);
+}
+
+const XDeviceList& DeviceListCacheX11::GetXDeviceList(Display* display) {
+  XDeviceList& x_dev_list = x_dev_list_;
+  // Note that the function can be called before any update has taken place.
+  if (!x_dev_list.devices && !x_dev_list.count)
+    x_dev_list.devices.reset(XListInputDevices(display, &x_dev_list.count));
+  return x_dev_list;
+}
+
+const XIDeviceList& DeviceListCacheX11::GetXI2DeviceList(Display* display) {
+  XIDeviceList& xi_dev_list = xi_dev_list_;
+  if (!xi_dev_list.devices && !xi_dev_list.count) {
+    xi_dev_list.devices.reset(
+        XIQueryDevice(display, XIAllDevices, &xi_dev_list.count));
+  }
+  return xi_dev_list;
+}
+
+}  // namespace ui
+