Remove unused brightness control from HardwareComposer

namespace {

const char kBacklightBrightnessSysFile[] =

    "/sys/class/leds/lcd-backlight/brightness";

const char kDvrPerformanceProperty[] = "sys.dvr.performance";

const char kDvrStandaloneProperty[] = "ro.boot.vr";

  EnableVsync(true);

  // TODO(skiazyk): We need to do something about accessing this directly,

  // supposedly there is a backlight service on the way.

  // TODO(steventhomas): When we change the backlight setting, will surface

  // flinger (or something else) set it back to its original value once we give

  // control of the display back to surface flinger?

  SetBacklightBrightness(255);

  // Trigger target-specific performance mode change.

  property_set(kDvrPerformanceProperty, "performance");

}

  bool thread_policy_setup =

      SetThreadPolicy("graphics:high", "/system/performance");

#if ENABLE_BACKLIGHT_BRIGHTNESS

  // TODO(hendrikw): This isn't required at the moment. It's possible that there

  //                 is another method to access this when needed.

  // Open the backlight brightness control sysfs node.

  backlight_brightness_fd_ = LocalHandle(kBacklightBrightnessSysFile, O_RDWR);

  ALOGW_IF(!backlight_brightness_fd_,

           "HardwareComposer: Failed to open backlight brightness control: %s",

           strerror(errno));

#endif  // ENABLE_BACKLIGHT_BRIGHTNESS

  // Create a timerfd based on CLOCK_MONOTINIC.

  vsync_sleep_timer_fd_.Reset(timerfd_create(CLOCK_MONOTONIC, 0));

  LOG_ALWAYS_FATAL_IF(

  vsync_callback_ = callback;

}

void HardwareComposer::SetBacklightBrightness(int brightness) {

  if (backlight_brightness_fd_) {

    std::array<char, 32> text;

    const int length = snprintf(text.data(), text.size(), "%d", brightness);

    write(backlight_brightness_fd_.Get(), text.data(), length);

  }

}

Return<void> HardwareComposer::ComposerCallback::onHotplug(

    Hwc2::Display display, IComposerCallback::Connection conn) {

  // Our first onHotplug callback is always for the primary display.

  HWC::Error Validate(hwc2_display_t display);

  HWC::Error Present(hwc2_display_t display);

  void SetBacklightBrightness(int brightness);

  void PostLayers();

  void PostThread();

  // notified via post_thread_wait_.

  bool boot_finished_ = false;

  // Backlight LED brightness sysfs node.

  pdx::LocalHandle backlight_brightness_fd_;

  // VSync sleep timerfd.

  pdx::LocalHandle vsync_sleep_timer_fd_;