chromeos: Add operations to monitor the screen orientation.

content/browser/sensors/sensors_source_chromeos.h

+// Copyright (c) 2011 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 CONTENT_BROWSER_CHROMEOS_SENSORS_SOURCE_CHROMEOS_H_
+#define CONTENT_BROWSER_CHROMEOS_SENSORS_SOURCE_CHROMEOS_H_
+
+#include "base/memory/ref_counted.h"
+
+#include <string>
+
+namespace dbus {
+class Bus;
+class ObjectProxy;
+class Signal;
+}  // namespace
+
+namespace sensors {

[sky, 2011/09/12 21:21:19]

I'm not familiar with sensors, and it doesn't look like this directory exists
yet. Could you get someone that is familiar with sensors to review this?

[cwolfe, 2011/09/12 22:15:55]

Whoops. Fixed the macros.

I added content/browser/sensors a while back as an experimental framework for
the motion sensors system I'm working toward adding. The design doc is
unfortunately still pending.

+
+// Creates and manages a dbus signal receiver for device orientation changes,
+// and eventually receives data for other motion-related sensors.
+class SensorsSourceChromeos
+    : public base::RefCountedThreadSafe<SensorsSourceChromeos> {
+ public:
+  // Creates an inactive sensors source.
+  SensorsSourceChromeos();
+
+  // Initializes this sensor source and begins listening for signals.
+  // Returns true if the

[sky, 2011/09/12 21:21:19]

update comment.

[cwolfe, 2011/09/12 22:15:55]

Done.

+  //
+  // The sensor source currently performs DBus operations using
+  // BrowserThread::IO, which have been started before calling this method.
+  bool Init();
+
+  // Shuts down this sensors source and the underlying DBus connection.
+  void Stop();
+
+ private:
+  friend class base::RefCountedThreadSafe<SensorsSourceChromeos>;
+  virtual ~SensorsSourceChromeos();
+
+  // Called by dbus:: when an orientation change signal is received.
+  void OrientationChangedReceived(dbus::Signal* signal);
+
+  // Called by dbus:: when the orientation change signal is initially connected.
+  void OrientationChangedConnected(const std::string& interface_name,
+                                   const std::string& signal_name,
+                                   bool success);
+
+  scoped_refptr<dbus::Bus> bus_;
+  dbus::ObjectProxy* sensors_proxy_;
+
+  DISALLOW_COPY_AND_ASSIGN(SensorsSourceChromeos);
+};
+
+}  // namespace sensors
+
+#endif  // CONTENT_BROWSER_CHROMEOS_SENSORS_SOURCE_CHROMEOS_H_