Revert "Reland "[On-device adaptive brightness] Implement an AlsReader to ambient light.""

This reverts commit a609f4ac.

Reason for revert: <INSERT REASONING HERE>

Original change's description:
> Reland "[On-device adaptive brightness] Implement an AlsReader to ambient light."
> 
> 
> Original change's description:
> > Revert "[On-device adaptive brightness] Implement an AlsReader to ambient light."
> > 
> > This reverts commit ea692f36.
> > 
> > Reason for revert: broke the linux-chromeos-dbg (https://ci.chromium.org/p/chromium/builders/luci.chromium.ci/linux-chromeos-dbg/7744)
> > 
> > Original change's description:
> > > [On-device adaptive brightness] Implement an AlsReader to ambient light.
> > > 
> > > 
> > > Bug: 881215
> > > Change-Id: I1cd5bf7ea517e426b54df1f4ebbb5a843b991dbe
> > > Reviewed-on: https://chromium-review.googlesource.com/1209000
> > > Reviewed-by: Michael Martis <martis@chromium.org>
> > > Reviewed-by: Dan Erat <derat@chromium.org>
> > > Commit-Queue: Jia Meng <jiameng@chromium.org>
> > > Cr-Commit-Position: refs/heads/master@{#589843}
> > 
> > TBR=derat@chromium.org,jiameng@chromium.org,martis@chromium.org
> > 
> > Change-Id: Id12029b7d3b46eaed672525fe0bcf96960ea143c
> > No-Presubmit: true
> > No-Tree-Checks: true
> > No-Try: true
> > Bug: 881215
> > Reviewed-on: https://chromium-review.googlesource.com/1215603
> > Reviewed-by: Jia Meng <jiameng@chromium.org>
> > Commit-Queue: Jia Meng <jiameng@chromium.org>
> > Cr-Commit-Position: refs/heads/master@{#589850}
> 
> TBR=derat@chromium.org,jiameng@chromium.org,martis@chromium.org
> 
> Change-Id: I8f170731509b2b23d469519fd45d5876175111d5
> No-Presubmit: true
> No-Tree-Checks: true
> No-Try: true
> Bug: 881215
> Reviewed-on: https://chromium-review.googlesource.com/1217962
> Reviewed-by: Jia Meng <jiameng@chromium.org>
> Commit-Queue: Jia Meng <jiameng@chromium.org>
> Cr-Commit-Position: refs/heads/master@{#590115}

TBR=derat@chromium.org,jiameng@chromium.org,martis@chromium.org

Change-Id: Idc8436b6fcf1140e5c30912d4c0727e867c2cb9b
No-Presubmit: true
No-Tree-Checks: true
No-Try: true
Bug: 881215
Reviewed-on: https://chromium-review.googlesource.com/1217982Reviewed-by: Jia Meng <jiameng@chromium.org>
Commit-Queue: Jia Meng <jiameng@chromium.org>
Cr-Commit-Position: refs/heads/master@{#590116}

chrome/browser/chromeos/BUILD.gn

@@ -1580,8 +1580,6 @@ source_set("chromeos") {
     "policy/weekly_time/weekly_time_interval.h",
     "policy/wildcard_login_checker.cc",
     "policy/wildcard_login_checker.h",
-    "power/auto_screen_brightness/als_reader.cc",
-    "power/auto_screen_brightness/als_reader.h",
     "power/cpu_data_collector.cc",
     "power/cpu_data_collector.h",
     "power/extension_event_observer.cc",
@@ -2255,7 +2253,6 @@ source_set("unit_tests") {
     "policy/weekly_time/time_utils_unittest.cc",
     "policy/weekly_time/weekly_time_interval_unittest.cc",
     "policy/weekly_time/weekly_time_unittest.cc",
-    "power/auto_screen_brightness/als_reader_unittest.cc",
     "power/cpu_data_collector_unittest.cc",
     "power/extension_event_observer_unittest.cc",
     "power/ml/adaptive_screen_brightness_manager_unittest.cc",

chrome/browser/chromeos/power/auto_screen_brightness/als_reader.cc

-// Copyright 2018 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/chromeos/power/auto_screen_brightness/als_reader.h"
-
-#include "base/command_line.h"
-#include "base/files/file_util.h"
-#include "base/macros.h"
-#include "base/process/launch.h"
-#include "base/strings/string_number_conversions.h"
-#include "base/strings/string_split.h"
-#include "base/strings/string_util.h"
-#include "base/task/post_task.h"
-#include "content/public/browser/browser_thread.h"
-
-namespace chromeos {
-namespace power {
-namespace auto_screen_brightness {
-
-namespace {
-// Returns whether the device has an ALS that we can use. This should run in
-// another thread to be non-blocking to the main thread.
-bool IsAlsEnabled() {
-  DCHECK(!content::BrowserThread::CurrentlyOn(content::BrowserThread::UI));
-  base::CommandLine command_line{
-      base::FilePath(FILE_PATH_LITERAL("check_powerd_config"))};
-  command_line.AppendArg("--ambient_light_sensor");
-  int exit_code = 0;
-  std::string output;  // Not used.
-  const bool result =
-      base::GetAppOutputWithExitCode(command_line, &output, &exit_code);
-
-  if (!result) {
-    LOG(ERROR) << "Cannot run check_powerd_config --ambient_light_sensor";
-    return false;
-  }
-  return exit_code == 0;
-}
-
-// Returns whether the ALS step config is what we need. This function is only
-// called if an ALS is enabled. This should run in another thread to be
-// non-blocking to the main thread.
-// TODO(jiameng): we assume one specific device now, and only check if the
-// number of steps is 7.
-bool VerifyAlsConfig() {
-  DCHECK(!content::BrowserThread::CurrentlyOn(content::BrowserThread::UI));
-  base::CommandLine command_line{
-      base::FilePath(FILE_PATH_LITERAL("check_powerd_config"))};
-  command_line.AppendArg("--internal_backlight_ambient_light_steps");
-  int exit_code = 0;
-  std::string output;
-  const bool result =
-      base::GetAppOutputWithExitCode(command_line, &output, &exit_code);
-
-  if (!result || exit_code != 0) {
-    LOG(ERROR) << "Cannot run check_powerd_config "
-                  "--internal_backlight_ambient_light_steps";
-    return false;
-  }
-
-  const std::vector<base::StringPiece> num_steps = base::SplitStringPiece(
-      output, "\n", base::TRIM_WHITESPACE, base::SPLIT_WANT_ALL);
-  return num_steps.size() == 7;
-}
-
-// Returns ALS path. This should run in another thread to be non-blocking to the
-// main thread.
-std::string GetAlsPath() {
-  DCHECK(!content::BrowserThread::CurrentlyOn(content::BrowserThread::UI));
-  base::CommandLine command_line{
-      base::FilePath(FILE_PATH_LITERAL("backlight_tool"))};
-  command_line.AppendArg("--get_ambient_light_path");
-  int exit_code = 0;
-  std::string output;
-  const bool result =
-      base::GetAppOutputWithExitCode(command_line, &output, &exit_code);
-  if (!result) {
-    LOG(ERROR) << "Cannot run backlight_tool --get_ambient_light_path";
-    return "";
-  }
-
-  if (exit_code != 0 || output.empty()) {
-    LOG(ERROR) << "Missing ambient light path";
-    return "";
-  }
-
-  return output;
-}
-
-// Reads ALS value from |ambient_light_path|. This should run in another thread
-// to be non-blocking to the main thread.
-std::string ReadAlsFromFile(const base::FilePath& ambient_light_path) {
-  DCHECK(!content::BrowserThread::CurrentlyOn(content::BrowserThread::UI));
-  std::string data;
-  if (!base::ReadFileToString(ambient_light_path, &data)) {
-    LOG(ERROR) << "Cannot read ALS value";
-    return "";
-  }
-  return data;
-}
-}  // namespace
-
-constexpr int AlsReader::kMaxInitialAttempts;
-
-AlsReader::AlsReader()
-    : als_task_runner_(base::CreateSequencedTaskRunnerWithTraits(
-          {base::TaskPriority::BEST_EFFORT, base::MayBlock(),
-           base::TaskShutdownBehavior::SKIP_ON_SHUTDOWN})),
-      weak_ptr_factory_(this) {}
-
-AlsReader::~AlsReader() = default;
-
-void AlsReader::AddObserver(Observer* const observer) {
-  DCHECK(observer);
-  observers_.AddObserver(observer);
-}
-
-void AlsReader::RemoveObserver(Observer* const observer) {
-  DCHECK(observer);
-  observers_.RemoveObserver(observer);
-}
-
-AlsReader::AlsInitStatus AlsReader::GetInitStatus() const {
-  return status_;
-}
-
-void AlsReader::Init() {
-  base::PostTaskAndReplyWithResult(
-      als_task_runner_.get(), FROM_HERE, base::BindOnce(&IsAlsEnabled),
-      base::BindOnce(&AlsReader::OnAlsEnableCheckDone, AsWeakPtr()));
-}
-
-void AlsReader::SetTaskRunnerForTesting(
-    const scoped_refptr<base::SequencedTaskRunner> task_runner) {
-  als_task_runner_ = task_runner;
-  als_timer_.SetTaskRunner(task_runner);
-}
-
-void AlsReader::InitForTesting(const base::FilePath& ambient_light_path) {
-  DCHECK(!ambient_light_path.empty());
-  ambient_light_path_ = ambient_light_path;
-  status_ = AlsInitStatus::kSuccess;
-  OnInitializationComplete();
-  ReadAlsPeriodically();
-}
-
-base::WeakPtr<AlsReader> AlsReader::AsWeakPtr() {
-  return weak_ptr_factory_.GetWeakPtr();
-}
-
-void AlsReader::OnAlsEnableCheckDone(const bool is_enabled) {
-  if (!is_enabled) {
-    status_ = AlsInitStatus::kDisabled;
-    OnInitializationComplete();
-    return;
-  }
-
-  base::PostTaskAndReplyWithResult(
-      als_task_runner_.get(), FROM_HERE, base::BindOnce(&VerifyAlsConfig),
-      base::BindOnce(&AlsReader::OnAlsConfigCheckDone, AsWeakPtr()));
-}
-
-void AlsReader::OnAlsConfigCheckDone(const bool is_config_valid) {
-  if (!is_config_valid) {
-    status_ = AlsInitStatus::kIncorrectConfig;
-    OnInitializationComplete();
-    return;
-  }
-
-  RetryAlsPath();
-}
-
-void AlsReader::OnAlsPathReadAttempted(const std::string& path) {
-  if (!path.empty()) {
-    ambient_light_path_ = base::FilePath(path);
-    status_ = AlsInitStatus::kSuccess;
-    OnInitializationComplete();
-    ReadAlsPeriodically();
-    return;
-  }
-
-  ++num_failed_initialization_;
-
-  if (num_failed_initialization_ == kMaxInitialAttempts) {
-    status_ = AlsInitStatus::kMissingPath;
-    OnInitializationComplete();
-    return;
-  }
-
-  als_timer_.Start(FROM_HERE, kAlsFileCheckingInterval, this,
-                   &AlsReader::RetryAlsPath);
-}
-
-void AlsReader::RetryAlsPath() {
-  base::PostTaskAndReplyWithResult(
-      als_task_runner_.get(), FROM_HERE, base::BindOnce(&GetAlsPath),
-      base::BindOnce(&AlsReader::OnAlsPathReadAttempted, AsWeakPtr()));
-}
-
-void AlsReader::OnInitializationComplete() {
-  DCHECK_NE(status_, AlsInitStatus::kInProgress);
-  for (auto& observer : observers_)
-    observer.OnAlsReaderInitialized(status_);
-}
-
-void AlsReader::ReadAlsPeriodically() {
-  base::PostTaskAndReplyWithResult(
-      als_task_runner_.get(), FROM_HERE,
-      base::BindOnce(&ReadAlsFromFile, ambient_light_path_),
-      base::BindOnce(&AlsReader::OnAlsRead, AsWeakPtr()));
-}
-
-void AlsReader::OnAlsRead(const std::string& data) {
-  std::string trimmed_data;
-  base::TrimWhitespaceASCII(data, base::TRIM_ALL, &trimmed_data);
-  int value = 0;
-  if (base::StringToInt(trimmed_data, &value)) {
-    for (auto& observer : observers_)
-      observer.OnAmbientLightUpdated(value);
-  }
-  als_timer_.Start(FROM_HERE, kAlsPollInterval, this,
-                   &AlsReader::ReadAlsPeriodically);
-}
-
-}  // namespace auto_screen_brightness
-}  // namespace power
-}  // namespace chromeos

chrome/browser/chromeos/power/auto_screen_brightness/als_reader.h

-// Copyright 2018 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.
-
-#ifndef CHROME_BROWSER_CHROMEOS_POWER_AUTO_SCREEN_BRIGHTNESS_ALS_READER_H_
-#define CHROME_BROWSER_CHROMEOS_POWER_AUTO_SCREEN_BRIGHTNESS_ALS_READER_H_
-
-#include "base/files/file_path.h"
-#include "base/macros.h"
-#include "base/memory/scoped_refptr.h"
-#include "base/memory/weak_ptr.h"
-#include "base/observer_list.h"
-#include "base/sequenced_task_runner.h"
-#include "base/task_runner_util.h"
-#include "base/timer/timer.h"
-
-namespace chromeos {
-namespace power {
-namespace auto_screen_brightness {
-
-// AlsReader periodically reads lux values from the ambient light sensor (ALS)
-// if powerd has been configured to use it.
-class AlsReader {
- public:
-  // ALS file location may not be ready immediately, so we retry every
-  // |kAlsFileCheckingInterval| until |kMaxInitialAttempts| is reached, then
-  // we give up.
-  static constexpr base::TimeDelta kAlsFileCheckingInterval =
-      base::TimeDelta::FromSeconds(1);
-  static constexpr int kMaxInitialAttempts = 20;
-
-  // Interval for polling ambient light values.
-  static constexpr base::TimeDelta kAlsPollInterval =
-      base::TimeDelta::FromSeconds(1);
-
-  // Status of AlsReader initialization.
-  enum class AlsInitStatus {
-    kSuccess = 0,
-    kInProgress = 1,
-    kDisabled = 2,
-    kIncorrectConfig = 3,
-    kMissingPath = 4,
-    kMaxValue = kMissingPath
-  };
-
-  // Observers should take WeakPtr of AlsReader and remove themselves in
-  // observers' destructors if AlsReader hasn't be destructed.
-  class Observer : public base::CheckedObserver {
-   public:
-    Observer() = default;
-    ~Observer() override = default;
-    virtual void OnAmbientLightUpdated(int lux) = 0;
-    virtual void OnAlsReaderInitialized(AlsInitStatus status) = 0;
-
-   private:
-    DISALLOW_COPY_AND_ASSIGN(Observer);
-  };
-
-  AlsReader();
-  ~AlsReader();
-
-  // Adds or removes an observer.
-  void AddObserver(Observer* observer);
-  void RemoveObserver(Observer* observer);
-
-  // An observer can call this method to check if ALS has been properly
-  // initialized and ready to use.
-  AlsInitStatus GetInitStatus() const;
-
-  // Checks if an ALS is enabled, and if the config is valid . Also
-  // reads ambient light file path.
-  void Init();
-
-  // Sets the task runner for testing purpose.
-  void SetTaskRunnerForTesting(
-      scoped_refptr<base::SequencedTaskRunner> task_runner);
-
-  // Sets ambient light path for testing purpose and initialize. This will cause
-  // all the checks to be skipped, i.e. whether ALS is enabled and if config is
-  // valid.
-  void InitForTesting(const base::FilePath& ambient_light_path);
-
-  base::WeakPtr<AlsReader> AsWeakPtr();
-
- private:
-  friend class AlsReaderTest;
-
-  // Called when we've checked whether ALS is enabled.
-  void OnAlsEnableCheckDone(bool is_enabled);
-
-  // Called when we've checked whether ALS config is valid.
-  void OnAlsConfigCheckDone(bool is_config_valid);
-
-  // Called when we've tried to read ALS path. If |path| is empty, it would
-  // reschedule another attempt up to |kMaxInitialAttempts|.
-  void OnAlsPathReadAttempted(const std::string& path);
-
-  // Tries to read ALS path.
-  void RetryAlsPath();
-
-  // Notifies all observers with |status_| after AlsReader is initialized.
-  void OnInitializationComplete();
-
-  // Polls ambient light periodically and notifies all observers if a sample is
-  // read.
-  void ReadAlsPeriodically();
-
-  // This is called after ambient light (represented as |data|) is sampled. It
-  // parses |data| to int, notifies its observers and starts |als_timer_| for
-  // next sample.
-  void OnAlsRead(const std::string& data);
-
-  AlsInitStatus status_ = AlsInitStatus::kInProgress;
-  base::FilePath ambient_light_path_;
-  int num_failed_initialization_ = 0;
-
-  // Timer used to retry initialization and also for periodic ambient light
-  // sampling.
-  base::OneShotTimer als_timer_;
-  scoped_refptr<base::SequencedTaskRunner> als_task_runner_;
-  base::ObserverList<Observer> observers_;
-  base::WeakPtrFactory<AlsReader> weak_ptr_factory_;
-
-  DISALLOW_COPY_AND_ASSIGN(AlsReader);
-};
-
-}  // namespace auto_screen_brightness
-}  // namespace power
-}  // namespace chromeos
-
-#endif  // CHROME_BROWSER_CHROMEOS_POWER_AUTO_SCREEN_BRIGHTNESS_ALS_READER_H_

chrome/browser/chromeos/power/auto_screen_brightness/als_reader_unittest.cc

-// Copyright 2018 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/chromeos/power/auto_screen_brightness/als_reader.h"
-
-#include "base/files/file_path.h"
-#include "base/files/file_util.h"
-#include "base/files/scoped_temp_dir.h"
-#include "base/strings/string_number_conversions.h"
-#include "base/test/scoped_task_environment.h"
-#include "base/threading/sequenced_task_runner_handle.h"
-#include "testing/gtest/include/gtest/gtest.h"
-
-namespace chromeos {
-namespace power {
-namespace auto_screen_brightness {
-
-namespace {
-
-class TestObserver : public AlsReader::Observer {
- public:
-  TestObserver() {}
-  ~TestObserver() override = default;
-
-  // AlsReader::Observer overrides:
-  void OnAmbientLightUpdated(const int lux) override {
-    ambient_light_ = lux;
-    ++num_received_ambient_lights_;
-  }
-
-  void OnAlsReaderInitialized(const AlsReader::AlsInitStatus status) override {
-    status_ = base::Optional<AlsReader::AlsInitStatus>(status);
-  }
-
-  int get_ambient_light() { return ambient_light_; }
-  int get_num_received_ambient_lights() { return num_received_ambient_lights_; }
-
-  AlsReader::AlsInitStatus get_status() {
-    CHECK(status_);
-    return status_.value();
-  }
-
- private:
-  int ambient_light_ = -1;
-  int num_received_ambient_lights_ = 0;
-  base::Optional<AlsReader::AlsInitStatus> status_;
-
-  DISALLOW_COPY_AND_ASSIGN(TestObserver);
-};
-}  // namespace
-
-class AlsReaderTest : public testing::Test {
- public:
-  AlsReaderTest()
-      : scoped_task_environment_(
-            std::make_unique<base::test::ScopedTaskEnvironment>(
-                base::test::ScopedTaskEnvironment::MainThreadType::MOCK_TIME)) {
-    CHECK(temp_dir_.CreateUniqueTempDir());
-    ambient_light_path_ = temp_dir_.GetPath().Append("test_als");
-    als_reader_.SetTaskRunnerForTesting(base::SequencedTaskRunnerHandle::Get());
-    als_reader_.AddObserver(&test_observer_);
-    als_reader_.InitForTesting(ambient_light_path_);
-  }
-
-  ~AlsReaderTest() override = default;
-
- protected:
-  void WriteLux(int lux) {
-    const std::string lux_string = base::IntToString(lux);
-    const int bytes_written = base::WriteFile(
-        ambient_light_path_, lux_string.data(), lux_string.size());
-    ASSERT_EQ(bytes_written, static_cast<int>(lux_string.size()))
-        << "Wrote " << bytes_written << " byte(s) instead of "
-        << lux_string.size() << " to " << ambient_light_path_.value();
-  }
-
-  base::ScopedTempDir temp_dir_;
-  base::FilePath ambient_light_path_;
-
-  std::unique_ptr<base::test::ScopedTaskEnvironment> scoped_task_environment_;
-
-  TestObserver test_observer_;
-  AlsReader als_reader_;
-
- private:
-  DISALLOW_COPY_AND_ASSIGN(AlsReaderTest);
-};
-
-TEST_F(AlsReaderTest, CheckInitStatusAlsFileFound) {
-  EXPECT_EQ(AlsReader::AlsInitStatus::kSuccess, als_reader_.GetInitStatus());
-}
-
-TEST_F(AlsReaderTest, OnAlsReaderInitialized) {
-  EXPECT_EQ(AlsReader::AlsInitStatus::kSuccess, test_observer_.get_status());
-}
-
-TEST_F(AlsReaderTest, OneAlsValue) {
-  WriteLux(10);
-  scoped_task_environment_->RunUntilIdle();
-  EXPECT_EQ(10, test_observer_.get_ambient_light());
-  EXPECT_EQ(1, test_observer_.get_num_received_ambient_lights());
-}
-
-TEST_F(AlsReaderTest, TwoAlsValues) {
-  WriteLux(10);
-  // Ambient light is read immediately after initialization, and then
-  // periodically every |kAlsPollInterval|. Below we move time for half of
-  // |kAlsPollInterval| to ensure there is only one reading attempt.
-  scoped_task_environment_->FastForwardBy(AlsReader::kAlsPollInterval / 2);
-  EXPECT_EQ(10, test_observer_.get_ambient_light());
-  EXPECT_EQ(1, test_observer_.get_num_received_ambient_lights());
-
-  WriteLux(20);
-  // Now move time for another |kAlsPollInterval| to trigger another read.
-  scoped_task_environment_->FastForwardBy(AlsReader::kAlsPollInterval);
-  EXPECT_EQ(20, test_observer_.get_ambient_light());
-  EXPECT_EQ(2, test_observer_.get_num_received_ambient_lights());
-}
-
-}  // namespace auto_screen_brightness
-}  // namespace power
-}  // namespace chromeos