accelerometer: Update Ash Adding AccelerometerProviderMojo

This commit refactors ash/accelerometer that if group iioservice exists,
registering to Sensor Hal Dispatcher and waiting for samples updated
from iioservice instead of reading on sysfs files directly for
accelerometers' data.

BUG=b:172208566, b:172414227, b:168434557
TEST=builds, unit tests, and run on octopus & jacuzzi. Accels' samples
are updated successfully, and the auto-rotate screen is working.

Cq-Depend: chromium:2470222
Change-Id: Icf65705b2b8facb7fe79423edba163639e2ae45f
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2345942
Reviewed-by: Xiaoqian Dai <xdai@chromium.org>
Reviewed-by: Mitsuru Oshima <oshima@chromium.org>
Commit-Queue: Cheng-Hao Yang <chenghaoyang@chromium.org>
Cr-Commit-Position: refs/heads/master@{#827626}

ash/BUILD.gn

@@ -129,10 +129,15 @@ component("ash") {
     "accelerators/pre_target_accelerator_handler.h",
     "accelerators/spoken_feedback_toggler.cc",
     "accelerators/spoken_feedback_toggler.h",
+    "accelerometer/accelerometer_constants.h",
     "accelerometer/accelerometer_file_reader.cc",
     "accelerometer/accelerometer_file_reader.h",
+    "accelerometer/accelerometer_provider_mojo.cc",
+    "accelerometer/accelerometer_provider_mojo.h",
     "accelerometer/accelerometer_reader.cc",
     "accelerometer/accelerometer_reader.h",
+    "accelerometer/accelerometer_samples_observer.cc",
+    "accelerometer/accelerometer_samples_observer.h",
     "accelerometer/accelerometer_types.cc",
     "accelerometer/accelerometer_types.h",
     "accessibility/accessibility_controller_impl.cc",
@@ -1763,6 +1768,8 @@ component("ash") {
     # TODO(https://crbug.com/644336): Make CrasAudioHandler Chrome or Ash only.
     "//chromeos/audio",
     "//chromeos/components/multidevice/logging",
+    "//chromeos/components/sensors:sensors",
+    "//chromeos/components/sensors/mojom",
     "//chromeos/constants",
     "//chromeos/dbus",
 
@@ -1920,6 +1927,8 @@ test("ash_unittests") {
     "accelerators/accelerator_unittest.cc",
     "accelerators/magnifier_key_scroller_unittest.cc",
     "accelerators/spoken_feedback_toggler_unittest.cc",
+    "accelerometer/accelerometer_provider_mojo_unittest.cc",
+    "accelerometer/accelerometer_samples_observer_unittest.cc",
     "accessibility/accessibility_controller_unittest.cc",
     "accessibility/accessibility_focus_ring_controller_unittest.cc",
     "accessibility/accessibility_focus_ring_group_unittest.cc",
@@ -2366,6 +2375,9 @@ test("ash_unittests") {
     "//chromeos/components/bloom/public/cpp",
     "//chromeos/components/phonehub:test_support",
     "//chromeos/components/quick_answers:quick_answers",
+    "//chromeos/components/sensors:sensors",
+    "//chromeos/components/sensors:test_support",
+    "//chromeos/components/sensors/mojom",
     "//chromeos/constants",
     "//chromeos/dbus:test_support",
     "//chromeos/dbus/audio",

ash/DEPS

@@ -62,6 +62,7 @@ include_rules = [
   "+chromeos/components/proximity_auth/public/mojom",
   "+chromeos/components/quick_answers",
   "+chromeos/components/security_token_pin",
+  "+chromeos/components/sensors",
   "+chromeos/constants",
   # TODO(https://crbug.com/940810): Eliminate this.
   "+chromeos/dbus/initialize_dbus_client.h",

ash/accelerometer/accelerometer_constants.h

@@ -0,0 +1,23 @@
+// Copyright 2020 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 ASH_ACCELEROMETER_ACCELEROMETER_CONSTANTS_H_
+#define ASH_ACCELEROMETER_ACCELEROMETER_CONSTANTS_H_
+
+#include "ash/accelerometer/accelerometer_types.h"
+
+namespace ash {
+
+const char kAccelerometerChannels[][8] = {"accel_x", "accel_y", "accel_z"};
+
+// The number of axes for which there are accelerometer readings.
+constexpr uint32_t kNumberOfAxes = 3u;
+
+// The names of the accelerometers. Matches up with the enum AccelerometerSource
+// in ash/accelerometer/accelerometer_types.h.
+const char kLocationStrings[ACCELEROMETER_SOURCE_COUNT][5] = {"lid", "base"};
+
+}  // namespace ash
+
+#endif  // ASH_ACCELEROMETER_ACCELEROMETER_CONSTANTS_H_

ash/accelerometer/accelerometer_file_reader.cc

@@ -10,6 +10,7 @@
 #include <string>
 #include <vector>
 
+#include "ash/accelerometer/accelerometer_constants.h"
 #include "ash/public/cpp/tablet_mode_observer.h"
 #include "ash/shell.h"
 #include "ash/wm/tablet_mode/tablet_mode_controller.h"
@@ -26,6 +27,8 @@
 #include "base/strings/string_util.h"
 #include "base/strings/stringprintf.h"
 #include "base/system/sys_info.h"
+#include "base/task/task_traits.h"
+#include "base/task/thread_pool.h"
 #include "base/task_runner.h"
 #include "base/task_runner_util.h"
 #include "base/threading/platform_thread.h"
@@ -78,11 +81,6 @@ constexpr char kLegacyAccelerometerScanIndexPathFormatString[] =
 constexpr char kAccelerometerScanIndexPathFormatString[] =
     "scan_elements/in_accel_%s_index";
 
-// The names of the accelerometers. Matches up with the enum AccelerometerSource
-// in ash/accelerometer/accelerometer_types.h.
-constexpr char kAccelerometerNames[ACCELEROMETER_SOURCE_COUNT][5] = {"lid",
-                                                                     "base"};
-
 // The axes on each accelerometer. The order was changed on kernel 3.18+.
 constexpr char kAccelerometerAxes[][2] = {"x", "y", "z"};
 constexpr char kLegacyAccelerometerAxes[][2] = {"y", "x", "z"};
@@ -93,9 +91,6 @@ constexpr size_t kMaxAsciiUintLength = 21;
 // The size of individual values.
 constexpr size_t kDataSize = 2;
 
-// The number of axes for which there are acceleration readings.
-constexpr int kNumberOfAxes = 3;
-
 // The size of data in one reading of the accelerometers.
 constexpr int kSizeOfReading = kDataSize * kNumberOfAxes;
 
@@ -150,9 +145,14 @@ AccelerometerFileReader::AccelerometerFileReader()
     : observers_(
           new base::ObserverListThreadSafe<AccelerometerReader::Observer>()) {}
 
-void AccelerometerFileReader::PrepareAndInitialize(
-    scoped_refptr<base::SequencedTaskRunner> sequenced_task_runner) {
-  task_runner_ = sequenced_task_runner;
+void AccelerometerFileReader::PrepareAndInitialize() {
+  // AccelerometerReader is important for screen orientation so we need
+  // USER_VISIBLE priority.
+  // Use CONTINUE_ON_SHUTDOWN to avoid blocking shutdown since the datareading
+  // could get blocked on certain devices. See https://crbug.com/1023989.
+  task_runner_ = base::ThreadPool::CreateSequencedTaskRunner(
+      {base::MayBlock(), base::TaskPriority::USER_VISIBLE,
+       base::TaskShutdownBehavior::CONTINUE_ON_SHUTDOWN});
 
   initialization_state_ = State::INITIALIZING;
 
@@ -287,8 +287,8 @@ void AccelerometerFileReader::InitializeInternal() {
               3 * static_cast<int>(configuration_.count)) {
         const char* axis = legacy_cross_accel ? kLegacyAccelerometerAxes[j]
                                               : kAccelerometerAxes[j];
-        LOG(ERROR) << "Field index for " << kAccelerometerNames[i] << " "
-                   << axis << " axis out of bounds.";
+        LOG(ERROR) << "Field index for " << kLocationStrings[i] << " " << axis
+                   << " axis out of bounds.";
         initialization_state_ = State::FAILED;
         return;
       }
@@ -438,12 +438,12 @@ bool AccelerometerFileReader::InitializeAccelerometer(
     const base::FilePath& name,
     const std::string& location) {
   size_t config_index = 0;
-  for (; config_index < base::size(kAccelerometerNames); ++config_index) {
-    if (location == kAccelerometerNames[config_index])
+  for (; config_index < base::size(kLocationStrings); ++config_index) {
+    if (location == kLocationStrings[config_index])
       break;
   }
 
-  if (config_index >= base::size(kAccelerometerNames)) {
+  if (config_index >= base::size(kLocationStrings)) {
     LOG(ERROR) << "Unrecognized location: " << location << " for device "
                << name.MaybeAsASCII() << "\n";
     return false;
@@ -487,11 +487,11 @@ bool AccelerometerFileReader::InitializeLegacyAccelerometers(
       base::FilePath(kAccelerometerDevicePath).Append(name.BaseName());
   // Read configuration of each accelerometer axis from each accelerometer from
   // /sys/bus/iio/devices/iio:deviceX/.
-  for (size_t i = 0; i < base::size(kAccelerometerNames); ++i) {
+  for (size_t i = 0; i < base::size(kLocationStrings); ++i) {
     configuration_.has[i] = false;
     // Read scale of accelerometer.
-    std::string accelerometer_scale_path = base::StringPrintf(
-        kLegacyScaleNameFormatString, kAccelerometerNames[i]);
+    std::string accelerometer_scale_path =
+        base::StringPrintf(kLegacyScaleNameFormatString, kLocationStrings[i]);
     // Read the scale for all axes.
     int scale_divisor = 0;
     if (!ReadFileToInt(iio_path.Append(accelerometer_scale_path.c_str()),
@@ -507,9 +507,9 @@ bool AccelerometerFileReader::InitializeLegacyAccelerometers(
     configuration_.has[i] = true;
     for (size_t j = 0; j < base::size(kLegacyAccelerometerAxes); ++j) {
       configuration_.scale[i][j] = base::kMeanGravityFloat / scale_divisor;
-      std::string accelerometer_index_path = base::StringPrintf(
-          kLegacyAccelerometerScanIndexPathFormatString,
-          kLegacyAccelerometerAxes[j], kAccelerometerNames[i]);
+      std::string accelerometer_index_path =
+          base::StringPrintf(kLegacyAccelerometerScanIndexPathFormatString,
+                             kLegacyAccelerometerAxes[j], kLocationStrings[i]);
       if (!ReadFileToInt(iio_path.Append(accelerometer_index_path.c_str()),
                          &(configuration_.index[i][j]))) {
         configuration_.has[i] = false;

ash/accelerometer/accelerometer_file_reader.h

@@ -15,8 +15,6 @@
 
 namespace ash {
 
-enum class State { INITIALIZING, SUCCESS, FAILED };
-
 // Work that runs on a base::TaskRunner. It determines the accelerometer
 // configuration, and reads the data. Upon a successful read it will notify
 // all observers.
@@ -28,8 +26,7 @@ class AccelerometerFileReader : public AccelerometerProviderInterface,
   AccelerometerFileReader& operator=(const AccelerometerFileReader&) = delete;
 
   // AccelerometerProviderInterface:
-  void PrepareAndInitialize(
-      scoped_refptr<base::SequencedTaskRunner> sequenced_task_runner) override;
+  void PrepareAndInitialize() override;
   void AddObserver(AccelerometerReader::Observer* observer) override;
   void RemoveObserver(AccelerometerReader::Observer* observer) override;
   void StartListenToTabletModeController() override;
@@ -48,8 +45,9 @@ class AccelerometerFileReader : public AccelerometerProviderInterface,
   // Tracks if accelerometer initialization is completed.
   void CheckInitStatus();
 
-  // With ChromeOS EC lid angle driver present, accelerometer read is cancelled
-  // in clamshell mode, and triggered when entering tablet mode.
+  // With ChromeOS EC lid angle driver present, it's triggered when the device
+  // is physically used as a tablet (even thought its UI might be in clamshell
+  // mode), cancelled otherwise.
   void TriggerRead();
   void CancelRead();
 
@@ -130,9 +128,6 @@ class AccelerometerFileReader : public AccelerometerProviderInterface,
 
   void SetEmitEventsInternal(bool emit_events);
 
-  // The current initialization state of reader.
-  State initialization_state_ = State::INITIALIZING;
-
   // True if periodical accelerometer read is on.
   bool accelerometer_read_on_ = false;