Use chromeos accelerometer reader in athena and support only lid accelerometer.

BUG=380831
TEST=Glimmer/clapper still work, manually tested not having a base accelerometer.

Review URL: https://codereview.chromium.org/574113002

Cr-Commit-Position: refs/heads/master@{#295258}

athena/athena.gyp

@@ -88,8 +88,6 @@
         'screen/screen_manager_impl.cc',
         'system/background_controller.cc',
         'system/background_controller.h',
-        'system/device_socket_listener.cc',
-        'system/device_socket_listener.h',
         'system/network_selector.cc',
         'system/network_selector.h',
         'system/orientation_controller.cc',

athena/main/athena_launcher.cc

@@ -83,7 +83,7 @@ class VirtualKeyboardObserver : public keyboard::KeyboardControllerObserver {
   DISALLOW_COPY_AND_ASSIGN(VirtualKeyboardObserver);
 };
 
-void StartAthenaEnv(scoped_refptr<base::TaskRunner> file_runner) {
+void StartAthenaEnv(scoped_refptr<base::TaskRunner> blocking_task_runner) {
   athena::AthenaEnv::Create();
 
   base::CommandLine* command_line = base::CommandLine::ForCurrentProcess();
@@ -109,7 +109,7 @@ void StartAthenaEnv(scoped_refptr<base::TaskRunner> file_runner) {
 
   athena::InputManager::Create()->OnRootWindowCreated(root_window);
   athena::ScreenManager::Create(root_window);
-  athena::SystemUI::Create(file_runner);
+  athena::SystemUI::Create(blocking_task_runner);
   athena::WindowManager::Create();
   athena::AppRegistry::Create();
   SetupBackgroundImage();

athena/main/athena_main.cc

@@ -142,8 +142,9 @@ class AthenaBrowserMainDelegate : public extensions::ShellBrowserMainDelegate {
       extension_system->LoadApp(app_absolute_dir);
     }
 
-    athena::StartAthenaEnv(content::BrowserThread::GetMessageLoopProxyForThread(
-        content::BrowserThread::FILE));
+    athena::StartAthenaEnv(content::BrowserThread::GetBlockingPool()->
+        GetTaskRunnerWithShutdownBehavior(
+            base::SequencedWorkerPool::SKIP_ON_SHUTDOWN));
     athena::ExtensionsDelegate::CreateExtensionsDelegateForShell(context);
     athena::CreateVirtualKeyboardWithContext(context);
     athena::StartAthenaSessionWithContext(context);

athena/system/device_socket_listener.h

-// Copyright 2014 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 ATHENA_SYSTEM_DEVICE_SOCKET_LISTENER_H_
-#define ATHENA_SYSTEM_DEVICE_SOCKET_LISTENER_H_
-
-#include <string>
-
-#include "base/basictypes.h"
-#include "base/memory/ref_counted.h"
-
-namespace base {
-class TaskRunner;
-}
-
-namespace athena {
-
-// This class reads device-data from a socket.
-class DeviceSocketListener {
- public:
-  DeviceSocketListener(const std::string& socket_parth,
-                       size_t data_size);
-  virtual ~DeviceSocketListener();
-
-  static void CreateSocketManager(
-      scoped_refptr<base::TaskRunner> io_task_runner);
-  static void ShutdownSocketManager();
-
-  // This is called on the FILE thread when data is available on the socket.
-  // |data| is guaranteed to be of exactly |data_size| length. Note that the
-  // implementation must not mutate or free the data.
-  virtual void OnDataAvailableOnFILE(const void* data) = 0;
-
- protected:
-  void StartListening();
-  void StopListening();
-
- private:
-  const std::string socket_path_;
-  size_t data_size_;
-
-  DISALLOW_COPY_AND_ASSIGN(DeviceSocketListener);
-};
-
-}  // namespace athena
-
-#endif  // ATHENA_SYSTEM_DEVICE_SOCKET_LISTENER_H_

athena/system/orientation_controller.cc

@@ -14,112 +14,34 @@ namespace athena {
 
 namespace {
 
-// Path of the socket which the sensor daemon creates.
-const char kSocketPath[] = "/dev/sensors/orientation";
-
 // Threshold after which to rotate in a given direction.
 const int kGravityThreshold = 6.0f;
 
-// Minimum delay before triggering another orientation change.
-const int kOrientationChangeDelayNS = 500000000;
-
-enum SensorType {
-  SENSOR_ACCELEROMETER,
-  SENSOR_LIGHT,
-  SENSOR_PROXIMITY
-};
-
-// A sensor event from the device.
-struct DeviceSensorEvent {
-  // The type of event from the SensorType enum above.
-  int32_t type;
-
-  // The time in nanoseconds at which the event happened.
-  int64_t timestamp;
-
-  union {
-    // Accelerometer X,Y,Z values in SI units (m/s^2) including gravity.
-    // The orientation is described at
-    // http://www.html5rocks.com/en/tutorials/device/orientation/.
-    float data[3];
-
-    // Ambient (room) temperature in degrees Celcius.
-    float temperature;
-
-    // Proximity sensor distance in centimeters.
-    float distance;
-
-    // Ambient light level in SI lux units.
-    float light;
-  };
-};
-
 }  // namespace
 
-OrientationController::OrientationController()
-    : DeviceSocketListener(kSocketPath, sizeof(DeviceSensorEvent)),
-      last_orientation_change_time_(0),
-      shutdown_(false) {
-  CHECK(base::MessageLoopForUI::current());
-  ui_task_runner_ = base::MessageLoopForUI::current()->task_runner();
+OrientationController::OrientationController() {
 }
 
 void OrientationController::InitWith(
-    scoped_refptr<base::TaskRunner> file_task_runner) {
-  file_task_runner_ = file_task_runner;
-  file_task_runner->PostTask(
-      FROM_HERE,
-      base::Bind(&OrientationController::WatchForSocketPathOnFILE, this));
+    scoped_refptr<base::TaskRunner> blocking_task_runner) {
+  accelerometer_reader_.reset(
+      new chromeos::AccelerometerReader(blocking_task_runner, this));
 }
 
 OrientationController::~OrientationController() {
 }
 
 void OrientationController::Shutdown() {
-  CHECK(file_task_runner_.get());
-  StopListening();
-  file_task_runner_->PostTask(
-      FROM_HERE,
-      base::Bind(&OrientationController::ShutdownOnFILE, this));
-}
-
-void OrientationController::ShutdownOnFILE() {
-  shutdown_ = true;
-  watcher_.reset();
+  accelerometer_reader_.reset();
 }
 
-void OrientationController::WatchForSocketPathOnFILE() {
-  CHECK(base::MessageLoopForIO::current());
-  if (base::PathExists(base::FilePath(kSocketPath))) {
-    ui_task_runner_->PostTask(FROM_HERE,
-        base::Bind(&OrientationController::StartListening, this));
-  } else {
-    watcher_.reset(new base::FilePathWatcher);
-    watcher_->Watch(
-        base::FilePath(kSocketPath),
-        false,
-        base::Bind(&OrientationController::OnFilePathChangedOnFILE, this));
-  }
-}
-
-void OrientationController::OnFilePathChangedOnFILE(const base::FilePath& path,
-                                                    bool error) {
-  watcher_.reset();
-  if (error || shutdown_)
+void OrientationController::HandleAccelerometerUpdate(
+    const ui::AccelerometerUpdate& update) {
+  if (!update.has(ui::ACCELEROMETER_SOURCE_SCREEN))
     return;
 
-  ui_task_runner_->PostTask(FROM_HERE,
-      base::Bind(&OrientationController::StartListening, this));
-}
-
-void OrientationController::OnDataAvailableOnFILE(const void* data) {
-  const DeviceSensorEvent* event =
-      static_cast<const DeviceSensorEvent*>(data);
-  if (event->type != SENSOR_ACCELEROMETER)
-    return;
-
-  float gravity_x = event->data[0];
-  float gravity_y = event->data[1];
+  float gravity_x = update.get(ui::ACCELEROMETER_SOURCE_SCREEN).x();
+  float gravity_y = update.get(ui::ACCELEROMETER_SOURCE_SCREEN).y();
   gfx::Display::Rotation rotation;
   if (gravity_x < -kGravityThreshold) {
     rotation = gfx::Display::ROTATE_270;
@@ -134,24 +56,11 @@ void OrientationController::OnDataAvailableOnFILE(const void* data) {
     return;
   }
 
-  if (rotation == current_rotation_ ||
-      event->timestamp - last_orientation_change_time_ <
-          kOrientationChangeDelayNS) {
+  if (rotation == current_rotation_)
     return;
-  }
 
-  last_orientation_change_time_ = event->timestamp;
   current_rotation_ = rotation;
-  ui_task_runner_->PostTask(FROM_HERE,
-      base::Bind(&OrientationController::RotateOnUI, this, rotation));
-}
-
-void OrientationController::RotateOnUI(gfx::Display::Rotation rotation) {
-  ScreenManager* screen_manager = ScreenManager::Get();
-  // Since this is called from the FILE thread, the screen manager may no longer
-  // exist.
-  if (screen_manager)
-    screen_manager->SetRotation(rotation);
+  ScreenManager::Get()->SetRotation(rotation);
 }
 
 }  // namespace athena

athena/system/orientation_controller.h

@@ -5,16 +5,14 @@
 #ifndef ATHENA_SYSTEM_ORIENTATION_CONTROLLER_H_
 #define ATHENA_SYSTEM_ORIENTATION_CONTROLLER_H_
 
-#include "athena/system/device_socket_listener.h"
 #include "base/macros.h"
 #include "base/memory/ref_counted.h"
 #include "base/memory/scoped_ptr.h"
 #include "base/memory/weak_ptr.h"
+#include "chromeos/accelerometer/accelerometer_reader.h"
 #include "ui/gfx/display.h"
 
 namespace base {
-class FilePath;
-class FilePathWatcher;
 class TaskRunner;
 }
 
@@ -23,50 +21,23 @@ namespace athena {
 // Monitors accelerometers, detecting orientation changes. When a change is
 // detected rotates the root window to match.
 class OrientationController
-    : public DeviceSocketListener,
-      public base::RefCountedThreadSafe<OrientationController> {
+    : public chromeos::AccelerometerReader::Delegate {
  public:
   OrientationController();
-
-  void InitWith(scoped_refptr<base::TaskRunner> file_task_runner);
-
-  void Shutdown();
-
- private:
-  friend class base::RefCountedThreadSafe<OrientationController>;
-
   virtual ~OrientationController();
 
-  void ShutdownOnFILE();
-  // Watch for the socket path to be created, called on the FILE thread.
-  void WatchForSocketPathOnFILE();
-  void OnFilePathChangedOnFILE(const base::FilePath& path, bool error);
-
-  // Overridden from device::DeviceSocketListener:
-  virtual void OnDataAvailableOnFILE(const void* data) OVERRIDE;
+  void InitWith(scoped_refptr<base::TaskRunner> blocking_task_runner);
+  void Shutdown();
 
-  // Rotates the display to |rotation|, called on the UI thread.
-  void RotateOnUI(gfx::Display::Rotation rotation);
+  // chromeos::AccelerometerReader::Delegate
+  virtual void HandleAccelerometerUpdate(
+      const ui::AccelerometerUpdate& update) OVERRIDE;
 
+ private:
   // The last configured rotation.
   gfx::Display::Rotation current_rotation_;
 
-  // The timestamp of the last applied orientation change.
-  int64_t last_orientation_change_time_;
-
-  // True if the OrientaionController has already been shutdown.
-  // This is initialized on UI thread, but must be accessed / modified
-  // only on FILE thread.
-  bool shutdown_;
-
-  // A task runner for the UI thread.
-  scoped_refptr<base::TaskRunner> ui_task_runner_;
-
-  // A task runner for the FILE thread.
-  scoped_refptr<base::TaskRunner> file_task_runner_;
-
-  // File path watcher used to detect when sensors are present.
-  scoped_ptr<base::FilePathWatcher> watcher_;
+  scoped_ptr<chromeos::AccelerometerReader> accelerometer_reader_;
 
   DISALLOW_COPY_AND_ASSIGN(OrientationController);
 };

athena/system/system_ui_impl.cc

@@ -6,7 +6,6 @@
 
 #include "athena/screen/public/screen_manager.h"
 #include "athena/system/background_controller.h"
-#include "athena/system/device_socket_listener.h"
 #include "athena/system/orientation_controller.h"
 #include "athena/system/power_button_controller.h"
 #include "athena/system/status_icon_container_view.h"
@@ -75,12 +74,12 @@ class SystemInfoView : public views::View {
 
 class SystemUIImpl : public SystemUI {
  public:
-  SystemUIImpl(scoped_refptr<base::TaskRunner> file_task_runner)
+  SystemUIImpl(scoped_refptr<base::TaskRunner> blocking_task_runner)
       : orientation_controller_(new OrientationController()),
         power_button_controller_(new PowerButtonController),
         background_container_(NULL),
         system_modal_container_(NULL) {
-    orientation_controller_->InitWith(file_task_runner);
+    orientation_controller_->InitWith(blocking_task_runner);
   }
 
   virtual ~SystemUIImpl() {
@@ -113,7 +112,7 @@ class SystemUIImpl : public SystemUI {
   }
 
  private:
-  scoped_refptr<OrientationController> orientation_controller_;
+  scoped_ptr<OrientationController> orientation_controller_;
   scoped_ptr<PowerButtonController> power_button_controller_;
   scoped_ptr<BackgroundController> background_controller_;
 
@@ -129,9 +128,9 @@ class SystemUIImpl : public SystemUI {
 }  // namespace
 
 // static
-SystemUI* SystemUI::Create(scoped_refptr<base::TaskRunner> file_task_runner) {
-  DeviceSocketListener::CreateSocketManager(file_task_runner);
-  SystemUIImpl* system_ui = new SystemUIImpl(file_task_runner);
+SystemUI* SystemUI::Create(
+    scoped_refptr<base::TaskRunner> blocking_task_runner) {
+  SystemUIImpl* system_ui = new SystemUIImpl(blocking_task_runner);
   instance = system_ui;
   system_ui->Init();
   return instance;
@@ -148,7 +147,6 @@ void SystemUI::Shutdown() {
   CHECK(instance);
   delete instance;
   instance = NULL;
-  DeviceSocketListener::ShutdownSocketManager();
 }
 
 }  // namespace athena

athena/test/athena_test_helper.cc

@@ -60,6 +60,7 @@ void AthenaTestHelper::SetUp(ui::ContextFactory* context_factory) {
   aura::test::EnvTestHelper(aura::Env::GetInstance())
       .SetInputStateLookup(scoped_ptr<aura::InputStateLookup>());
 
+  // TODO(oshima): Use a BlockingPool task runner.
   athena::StartAthenaEnv(file_thread_->message_loop_proxy());
   athena::ExtensionsDelegate::CreateExtensionsDelegateForTest();
   athena::StartAthenaSession(new SampleActivityFactory(),

chrome/browser/ui/views/athena/chrome_browser_main_extra_parts_athena.cc

@@ -38,8 +38,9 @@ class ChromeBrowserMainExtraPartsAthena : public ChromeBrowserMainExtraParts,
  private:
   // Overridden from ChromeBrowserMainExtraParts:
   virtual void PreProfileInit() OVERRIDE {
-    athena::StartAthenaEnv(content::BrowserThread::GetMessageLoopProxyForThread(
-        content::BrowserThread::FILE));
+    athena::StartAthenaEnv(content::BrowserThread::GetBlockingPool()->
+        GetTaskRunnerWithShutdownBehavior(
+            base::SequencedWorkerPool::SKIP_ON_SHUTDOWN));
   }
   virtual void PostProfileInit() OVERRIDE {
     if (!CommandLine::ForCurrentProcess()->HasSwitch(

chromeos/accelerometer/accelerometer_reader.cc

@@ -27,28 +27,29 @@ const base::FilePath::CharType kAccelerometerDevicePath[] =
 const base::FilePath::CharType kAccelerometerIioBasePath[] =
     FILE_PATH_LITERAL("/sys/bus/iio/devices/");
 
-// Files within the device in kAccelerometerIioBasePath containing the scales of
+// File within the device in kAccelerometerIioBasePath containing the scale of
 // the accelerometers.
-const base::FilePath::CharType kAccelerometerBaseScaleName[] =
-    FILE_PATH_LITERAL("in_accel_base_scale");
-const base::FilePath::CharType kAccelerometerLidScaleName[] =
-    FILE_PATH_LITERAL("in_accel_lid_scale");
+const base::FilePath::CharType kScaleNameFormatString[] = "in_accel_%s_scale";
 
 // The filename giving the path to read the scan index of each accelerometer
 // axis.
 const char kAccelerometerScanIndexPath[] =
     "scan_elements/in_accel_%s_%s_index";
 
-// The names of the accelerometers and axes in the order we want to read them.
-const char kAccelerometerNames[][5] = {"base", "lid"};
-const char kAccelerometerAxes[][2] = {"x", "y", "z"};
-const size_t kTriggerDataValues =
-    arraysize(kAccelerometerNames) * arraysize(kAccelerometerAxes);
-const size_t kTriggerDataLength = kTriggerDataValues * 2;
+// The names of the accelerometers. Matches up with the enum AccelerometerSource
+// in ui/accelerometer/accelerometer_types.h.
+const char kAccelerometerNames[ui::ACCELEROMETER_SOURCE_COUNT][5] = {
+    "lid", "base"};
+
+// The axes on each accelerometer.
+const char kAccelerometerAxes[][2] = {"y", "x", "z"};
 
 // The length required to read uint values from configuration files.
 const size_t kMaxAsciiUintLength = 21;
 
+// The size of individual values.
+const size_t kDataSize = 2;
+
 // The time to wait between reading the accelerometer.
 const int kDelayBetweenReadsMs = 100;
 
@@ -57,15 +58,14 @@ const float kMeanGravity = 9.80665f;
 
 // Reads |path| to the unsigned int pointed to by |value|. Returns true on
 // success or false on failure.
-bool ReadFileToUint(const base::FilePath& path, unsigned int* value) {
+bool ReadFileToInt(const base::FilePath& path, int* value) {
   std::string s;
   DCHECK(value);
   if (!base::ReadFileToString(path, &s, kMaxAsciiUintLength)) {
-    LOG(ERROR) << "Failed to read " << path.value();
     return false;
   }
   base::TrimWhitespaceASCII(s, base::TRIM_ALL, &s);
-  if (!base::StringToUint(s, value)) {
+  if (!base::StringToInt(s, value)) {
     LOG(ERROR) << "Failed to parse \"" << s << "\" from " << path.value();
     return false;
   }
@@ -90,41 +90,62 @@ bool DetectAndReadAccelerometerConfiguration(
 
   base::FilePath iio_path(base::FilePath(kAccelerometerIioBasePath).Append(
       device));
-  // Read accelerometer scales
-  if (!ReadFileToUint(iio_path.Append(kAccelerometerBaseScaleName),
-                      &(configuration->data.base_scale))) {
-    return false;
-  }
-  if (!ReadFileToUint(iio_path.Append(kAccelerometerLidScaleName),
-                      &(configuration->data.lid_scale))) {
-    return false;
-  }
-
-  // Read indices of each accelerometer axis from each accelerometer from
-  // /sys/bus/iio/devices/iio:deviceX/scan_elements/in_accel_{x,y,z}_%s_index
+  // Read configuration of each accelerometer axis from each accelerometer from
+  // /sys/bus/iio/devices/iio:deviceX/.
   for (size_t i = 0; i < arraysize(kAccelerometerNames); ++i) {
+    // Read scale of accelerometer.
+    std::string accelerometer_scale_path = base::StringPrintf(
+        kScaleNameFormatString, kAccelerometerNames[i]);
+    int scale_divisor;
+    if (!ReadFileToInt(iio_path.Append(accelerometer_scale_path.c_str()),
+        &scale_divisor)) {
+      configuration->data.has[i] = false;
+      continue;
+    }
+
+    configuration->data.has[i] = true;
+    configuration->data.count++;
     for (size_t j = 0; j < arraysize(kAccelerometerAxes); ++j) {
+      configuration->data.scale[i][j] = kMeanGravity / scale_divisor;
       std::string accelerometer_index_path = base::StringPrintf(
           kAccelerometerScanIndexPath, kAccelerometerAxes[j],
           kAccelerometerNames[i]);
-      unsigned int index = 0;
-      if (!ReadFileToUint(iio_path.Append(accelerometer_index_path.c_str()),
-                          &index)) {
+      if (!ReadFileToInt(iio_path.Append(accelerometer_index_path.c_str()),
+                         &(configuration->data.index[i][j]))) {
         return false;
       }
-      if (index >= kTriggerDataValues) {
-        LOG(ERROR) << "Field index from " << accelerometer_index_path
-                   << " out of bounds: " << index;
+    }
+  }
+
+  // Adjust the directions of accelerometers to match the AccelerometerUpdate
+  // type specified in ui/accelerometer/accelerometer_types.h.
+  configuration->data.scale[ui::ACCELEROMETER_SOURCE_SCREEN][0] *= -1.0f;
+  for (int i = 0; i < 3; ++i) {
+    configuration->data.scale[ui::ACCELEROMETER_SOURCE_ATTACHED_KEYBOARD][i] *=
+        -1.0f;
+  }
+
+  // Verify indices are within bounds.
+  for (int i = 0; i < ui::ACCELEROMETER_SOURCE_COUNT; ++i) {
+    if (!configuration->data.has[i])
+      continue;
+    for (int j = 0; j < 3; ++j) {
+      if (configuration->data.index[i][j] < 0 ||
+          configuration->data.index[i][j] >=
+              3 * static_cast<int>(configuration->data.count)) {
+        LOG(ERROR) << "Field index for " << kAccelerometerNames[i] << " "
+                   << kAccelerometerAxes[j] << " axis out of bounds.";
         return false;
       }
-      configuration->data.index.push_back(index);
     }
   }
+  configuration->data.length = kDataSize * 3 * configuration->data.count;
   return true;
 }
 
 bool ReadAccelerometer(
-    scoped_refptr<AccelerometerReader::Reading> reading) {
+    scoped_refptr<AccelerometerReader::Reading> reading,
+    size_t length) {
   // Initiate the trigger to read accelerometers simultaneously
   int bytes_written = base::WriteFile(
       base::FilePath(kAccelerometerTriggerPath), "1\n", 2);
@@ -135,10 +156,10 @@ bool ReadAccelerometer(
 
   // Read resulting sample from /dev/cros-ec-accel.
   int bytes_read = base::ReadFile(base::FilePath(kAccelerometerDevicePath),
-                                  reading->data, kTriggerDataLength);
-  if (bytes_read < static_cast<int>(kTriggerDataLength)) {
+                                  reading->data, length);
+  if (bytes_read < static_cast<int>(length)) {
     LOG(ERROR) << "Read " << bytes_read << " byte(s), expected "
-               << kTriggerDataLength << " bytes from accelerometer";
+               << length << " bytes from accelerometer";
     return false;
   }
   return true;
@@ -146,16 +167,24 @@ bool ReadAccelerometer(
 
 }  // namespace
 
-AccelerometerReader::ConfigurationData::ConfigurationData() {
+AccelerometerReader::ConfigurationData::ConfigurationData()
+    : count(0) {
+  for (int i = 0; i < ui::ACCELEROMETER_SOURCE_COUNT; ++i) {
+    has[i] = false;
+    for (int j = 0; j < 3; ++j) {
+      scale[i][j] = 0;
+      index[i][j] = -1;
+    }
+  }
 }
 
 AccelerometerReader::ConfigurationData::~ConfigurationData() {
 }
 
 AccelerometerReader::AccelerometerReader(
-    base::TaskRunner* task_runner,
+    base::TaskRunner* blocking_task_runner,
     AccelerometerReader::Delegate* delegate)
-    : task_runner_(task_runner),
+    : task_runner_(blocking_task_runner),
       delegate_(delegate),
       configuration_(new AccelerometerReader::Configuration()),
       weak_factory_(this) {
@@ -186,7 +215,8 @@ void AccelerometerReader::TriggerRead() {
       new AccelerometerReader::Reading());
   base::PostTaskAndReplyWithResult(task_runner_.get(),
                                    FROM_HERE,
-                                   base::Bind(&ReadAccelerometer, reading),
+                                   base::Bind(&ReadAccelerometer, reading,
+                                              configuration_->data.length),
                                    base::Bind(&AccelerometerReader::OnDataRead,
                                               weak_factory_.GetWeakPtr(),
                                               reading));
@@ -198,17 +228,19 @@ void AccelerometerReader::OnDataRead(
   DCHECK(!task_runner_->RunsTasksOnCurrentThread());
 
   if (success) {
-    int16* values = reinterpret_cast<int16*>(reading->data);
-    float lid_scale = kMeanGravity / configuration_->data.lid_scale;
-    update_.Set(ui::ACCELEROMETER_SOURCE_SCREEN,
-                -values[configuration_->data.index[4]] * lid_scale,
-                values[configuration_->data.index[3]] * lid_scale,
-                values[configuration_->data.index[5]] * lid_scale);
-    float base_scale = kMeanGravity / configuration_->data.base_scale;
-    update_.Set(ui::ACCELEROMETER_SOURCE_ATTACHED_KEYBOARD,
-                -values[configuration_->data.index[1]] * base_scale,
-                -values[configuration_->data.index[0]] * base_scale,
-                -values[configuration_->data.index[2]] * base_scale);
+    for (int i = 0; i < ui::ACCELEROMETER_SOURCE_COUNT; ++i) {
+      if (!configuration_->data.has[i])
+        continue;
+
+      int16* values = reinterpret_cast<int16*>(reading->data);
+      update_.Set(static_cast<ui::AccelerometerSource>(i),
+                  values[configuration_->data.index[i][0]] *
+                      configuration_->data.scale[i][0],
+                  values[configuration_->data.index[i][1]] *
+                      configuration_->data.scale[i][1],
+                  values[configuration_->data.index[i][2]] *
+                      configuration_->data.scale[i][2]);
+    }
     delegate_->HandleAccelerometerUpdate(update_);
   }
 

chromeos/accelerometer/accelerometer_reader.h

@@ -5,8 +5,6 @@
 #ifndef CHROMEOS_ACCELEROMETER_ACCELEROMETER_READER_H_
 #define CHROMEOS_ACCELEROMETER_ACCELEROMETER_READER_H_
 
-#include <vector>
-
 #include "base/memory/ref_counted.h"
 #include "base/memory/weak_ptr.h"
 #include "base/observer_list.h"
@@ -28,12 +26,20 @@ class CHROMEOS_EXPORT AccelerometerReader {
     ConfigurationData();
     ~ConfigurationData();
 
-    // Scale of accelerometers (i.e. raw value * 1.0f / scale = G's).
-    unsigned int base_scale;
-    unsigned int lid_scale;
+    // Number of accelerometers on device.
+    size_t count;
+
+    // Length of accelerometer updates.
+    size_t length;
+
+    // Which accelerometers are present on device.
+    bool has[ui::ACCELEROMETER_SOURCE_COUNT];
+
+    // Scale of accelerometers (i.e. raw value * scale = m/s^2).
+    float scale[ui::ACCELEROMETER_SOURCE_COUNT][3];
 
     // Index of each accelerometer axis in data stream.
-    std::vector<unsigned int> index;
+    int index[ui::ACCELEROMETER_SOURCE_COUNT][3];
   };
   typedef base::RefCountedData<ConfigurationData> Configuration;
   typedef base::RefCountedData<char[12]> Reading;