chromium/chrome/browser/ui/views/frame/webui_tab_strip_field_trial.cc

// Copyright 2020 The Chromium Authors
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.

#include "chrome/browser/ui/views/frame/webui_tab_strip_field_trial.h"

#include "base/feature_list.h"
#include "base/logging.h"
#include "build/build_config.h"
#include "build/chromeos_buildflags.h"
#include "chrome/browser/metrics/chrome_metrics_service_accessor.h"
#include "chrome/browser/ui/ui_features.h"

// Platform-specific headers for detecting tablet devices.
#if BUILDFLAG(IS_CHROMEOS_ASH)
#include "ash/public/cpp/tablet_mode.h"
#elif BUILDFLAG(IS_WIN)
#include <windows.h>
#endif  // BUILDFLAG(IS_CHROMEOS_ASH)

namespace {

#if BUILDFLAG(IS_WIN)

// Returns whether the screen supports touch input. Returns false if it
// couldn't be checked.
bool HasBuiltInTouchScreen() {
  int result = ::GetSystemMetrics(SM_DIGITIZER);

  // The |result| can be a combination of the following:
  // - NID_INTEGRATED_TOUCH: built-in touch screen
  // - NID_EXTERNAL_TOUCH: external touch screen or tablet
  // - NID_INTEGRATED_PEN: built-in pen support
  // - NID_EXTERNAL_PEN: external pen screen or tablet
  // - NID_MULTI_INPUT: not sure what this means
  // - NID_READY: currently ready to receive touch or pen input
  //
  // Ideally, we want to determine if a device is a tablet or
  // convertible. This means it supports entering system tablet mode.
  // There is no direct way to check this, however having a built-in
  // touch screen is a good proxy. Ignore pen digitizers; if a device
  // only supports pen input it probably isn't a tablet.

  return (result & NID_INTEGRATED_TOUCH) != 0;
}

#endif  // BUILDFLAG(IS_WIN)

}  // namespace

// static
void WebUITabStripFieldTrial::RegisterFieldTrialIfNecessary() { … }

WebUITabStripFieldTrial::WebUITabStripFieldTrial() { … }

// static
bool WebUITabStripFieldTrial::DeviceIsTabletModeCapable() { … }