Touch event flag should control only DOM event firing.

ui/base/touch/touch_enabled.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 "ui/base/touch/touch_enabled.h"
-
-#include "base/command_line.h"
-#include "base/logging.h"
-#include "ui/base/touch/touch_device.h"
-#include "ui/base/ui_base_switches.h"
-#include "ui/events/base_event_utils.h"
-#include "ui/events/event_switches.h"
-
-namespace ui {
-
-namespace {
-
-enum class TouchEventsStatus {
-  AUTO,
-  DISABLED,
-  ENABLED,
-};
-
-TouchEventsStatus ComputeTouchFlagStatus() {
-  auto* command_line = base::CommandLine::ForCurrentProcess();
-  const std::string touch_enabled_switch =
-      command_line->HasSwitch(switches::kTouchEvents) ?
-          command_line->GetSwitchValueASCII(switches::kTouchEvents) :
-          switches::kTouchEventsAuto;
-
-  if (touch_enabled_switch.empty() ||
-      touch_enabled_switch == switches::kTouchEventsEnabled) {
-    return TouchEventsStatus::ENABLED;
-  }
-
-  if (touch_enabled_switch == switches::kTouchEventsAuto)
-    return TouchEventsStatus::AUTO;
-
-  DLOG_IF(ERROR, touch_enabled_switch != switches::kTouchEventsDisabled) <<
-      "Invalid --touch-events option: " << touch_enabled_switch;
-  return TouchEventsStatus::DISABLED;
-}
-
-}  // namespace
-
-bool AreTouchEventsEnabled() {
-  static TouchEventsStatus touch_flag_status = ComputeTouchFlagStatus();
-
-  // The #touch-events flag is used to force and simulate the presence or
-  // absence of touch devices. Only if the flag is set to AUTO, we need to check
-  // for the actual availability of touch devices.
-  if (touch_flag_status == TouchEventsStatus::AUTO)
-    return GetTouchScreensAvailability() == TouchScreensAvailability::ENABLED;
-
-  return touch_flag_status == TouchEventsStatus::ENABLED;
-}
-
-}  // namespace ui
-