DeviceOrientation API on ChromeOS

content/public/browser/sensor_manager.h

+// Copyright 2014 The Chromium Authors. All rights reserved.

[timvolodine, 2014/11/07 03:27:39]

is there any chance we can put it in content/browser/device_sensors/ with the
other platform implementations?
if you need to provide updates you can use base::Callback<..> instead of
exposing the whole class. Alternatively you could pass the shared memory handle
to the delegate in ash/.

[jonross, 2014/11/07 19:59:37]

I'm going to go with the Callback suggestion.

content/ cannot depend on ash/, so I will need a small class in
content/public/browser. However to minimize it I think a delegate which ash can
register would be appropriate.

Delegate {
  GetInstance()
  SetInstance(Delegate)
  StartOrientation(Callback) = 0
  StopOrientation() = 0
}

This will let the logic of parsing the values move to
content/browser/device_sensors. It will also allow ash/ to only start listening
to the accelerometer once told to start.

I prefer this to the SharedMemory approach, as that would require exposing all
of the hardware buffers to ash/

+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#ifndef CONTENT_PUBLIC_BROWSER_SENSOR_MANAGER_H_
+#define CONTENT_PUBLIC_BROWSER_SENSOR_MANAGER_H_
+
+#include "base/macros.h"
+#include "base/synchronization/lock.h"
+#include "content/common/content_export.h"
+#include "content/common/device_sensors/device_orientation_hardware_buffer.h"
+#include "ui/gfx/geometry/vector3d_f.h"
+
+template <typename T>
+struct DefaultSingletonTraits;
+
+namespace content {
+
+// For platforms with a push API for accelerometer sensors. Received data is
+// placed in a shared memory buffer, which is read by the renderer process.
+class CONTENT_EXPORT SensorManager {

[timvolodine, 2014/11/07 03:27:39]

this is chrome OS specific right? so probably should be called
SensorManagerChromeOS.

+ public:
+  // Returns the SensorManager singleton
+  static SensorManager* GetInstance();
+
+  // Push sensor notifications to shared memory.
+  void OnAccelerationIncludingGravity(double x, double y, double z);
+
+  // Set the shared memory buffer for orientation events. Accelerometer events
+  // will begin being processed.
+  void StartFetchingDeviceOrientationData(
+      DeviceOrientationHardwareBuffer* buffer);
+
+  // Stop processing accelerometer events for orientation.
+  void StopFetchingDeviceOrientationData();
+
+ private:
+  friend class SensorManagerTest;
+  friend struct DefaultSingletonTraits<SensorManager>;
+
+  // Shared memory buffers, not owned.
+  DeviceOrientationHardwareBuffer* orientation_buffer_;
+
+  // Synchronize orientation_buffer_ across threads.
+  base::Lock orientation_buffer_lock_;
+
+  SensorManager();
+  virtual ~SensorManager();
+
+  DeviceOrientationHardwareBuffer* GetOrientationBufferForTest() {
+    return orientation_buffer_;
+  }
+
+  DISALLOW_COPY_AND_ASSIGN(SensorManager);
+};
+
+}  // namespace content
+
+#endif  // CONTENT_PUBLIC_BROWSER_SENSOR_MANAGER_H_