WebKit & WebCore part of the device motion implementation using the platform layer.

Source/WebCore/platform/chromium/support/WebDeviceMotionEventPump.h

+/*
+ * Copyright (C) 2013 Google Inc. All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions are
+ * met:
+ *
+ *     * Redistributions of source code must retain the above copyright
+ * notice, this list of conditions and the following disclaimer.
+ *     * Redistributions in binary form must reproduce the above
+ * copyright notice, this list of conditions and the following disclaimer
+ * in the documentation and/or other materials provided with the
+ * distribution.
+ *     * Neither the name of Google Inc. nor the names of its
+ * contributors may be used to endorse or promote products derived from
+ * this software without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+ * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+ * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+ * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+ * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+ * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+ * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+ * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+ * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+ * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+ * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ */
+
+#ifndef WebDeviceMotionEventPump_h
+#define WebDeviceMotionEventPump_h
+
+#include "Timer.h"
+#include <DeviceMotionController.h>
+#include <DeviceMotionData.h>
+#include <wtf/CurrentTime.h>
+#include <wtf/RefCounted.h>
+
+using WebCore::DeviceMotionController;
+using WebCore::DeviceMotionData;
+using WebCore::Timer;
+
+namespace WebKit {
+
+// TODO(timvolodine): implement a superclass for this, because we will also use

[Peter Beverloo, 2013/04/09 17:29:53]

nit: Blink style uses unattributed FIXMEs.

[timvolodine, 2013/04/10 19:06:12]

Done.

+// a pump for the device orientation events.
+class WebDeviceMotionEventPump {
+public:
+    static WebDeviceMotionEventPump& shared();
+
+    void start();
+    void stop();
+    WebCore::DeviceMotionData* lastDeviceMotionData();
+
+private:
+    static const double kPumpDelaySeconds = 0.1;
+
+    double m_delaySeconds;
+    double m_lastFireEventTimeMonotonic;
+    bool m_stopped;
+    WTF::RefPtr<DeviceMotionData> m_lastDeviceMotionData;
+    Timer<WebDeviceMotionEventPump> m_pumpTimer;
+
+    WebDeviceMotionEventPump(double delay_seconds);
+    ~WebDeviceMotionEventPump() { }

[Peter Beverloo, 2013/04/09 17:29:53]

The order here is a bit odd.  Could we define static methods first, then the
constructor/destructor, then other methods, then member variables?

[timvolodine, 2013/04/10 19:06:12]

Done.

+
+    void scheduleFireEvent();
+    void fireEvent(Timer<WebDeviceMotionEventPump>*);

[Peter Beverloo, 2013/04/09 17:29:53]

What do we need a pointer to the timer for?

[timvolodine, 2013/04/10 19:06:12]

this is stanard way of using the Timer class (i.e. it needs a function with
pointer)

+    bool shouldFireEvent();
+};
+
+} // namespace WebKit
+
+#endif