DeviceOrientation API on ChromeOS

ash/content/accelerometer/sensor_manager_delegate_chromeos.cc

+// 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.
+
+#include "ash/content/accelerometer/sensor_manager_delegate_chromeos.h"
+
+#include "ash/accelerometer/accelerometer_controller.h"
+#include "ash/shell.h"
+#include "content/public/browser/sensor_manager_delegate_chromeos.h"
+#include "ui/accelerometer/accelerometer_types.h"
+
+namespace ash {
+
+SensorManagerDelegateChromeOS::SensorManagerDelegateChromeOS() {
+  content::SensorManagerDelegateChromeOS::SetDelegate(this);
+}
+
+SensorManagerDelegateChromeOS::~SensorManagerDelegateChromeOS() {
+  // Ensure we have stopped observing when shutdown.
+  StopFetchingDeviceOrientationData();
+  // Content Shell will have closed itself, do not remove as delegate

[timvolodine, 2014/11/26 19:32:19]

nit: "." and the end
also not sure what this comment actually means?

[jonross, 2014/11/26 23:17:56]

When this class is being destructed, content::SensorManagerDelegateChromeOS will
have already been destructed. So calling SetDelegate(nullptr) to remove this
class as the delegate will cause a crash.

+}
+
+void SensorManagerDelegateChromeOS::OnAccelerometerUpdated(
+    const ui::AccelerometerUpdate& update) {
+  ui::AccelerometerSource source;
+
+  if (update.has(ui::ACCELEROMETER_SOURCE_SCREEN)) {
+    source = ui::ACCELEROMETER_SOURCE_SCREEN;
+  } else if (update.has(ui::ACCELEROMETER_SOURCE_ATTACHED_KEYBOARD)) {
+    source = ui::ACCELEROMETER_SOURCE_ATTACHED_KEYBOARD;
+  } else {
+    return;
+  }
+
+  orientation_callback_.Run(update.get(source).x(), update.get(source).y(),
+                            update.get(source).z());
+}
+
+void SensorManagerDelegateChromeOS::StartFetchingDeviceOrientationData(
+    const content::OrientationDataCallback& callback) {
+  DCHECK(orientation_callback_.is_null());
+  Shell::GetInstance()->accelerometer_controller()->AddObserver(this);
+  orientation_callback_ = callback;
+}
+
+void SensorManagerDelegateChromeOS::StopFetchingDeviceOrientationData() {
+  if (!orientation_callback_.is_null())
+    Shell::GetInstance()->accelerometer_controller()->RemoveObserver(this);
+  orientation_callback_.Reset();
+}
+
+}  // namespace ash