Implement the Blink part of the Device Motion API.

Source/modules/device_orientation/DeviceMotionDispatcher.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 DeviceMotionDispatcher_h
+#define DeviceMotionDispatcher_h
+
+#include "DeviceMotionData.h"
+#include "wtf/RefPtr.h"
+#include "wtf/Vector.h"
+#include <public/WebDeviceMotionListener.h>
+
+namespace WebKit {
+class WebDeviceMotionData;
+}
+
+namespace WebCore {
+
+class DeviceMotionController;
+class DeviceMotionData;
+
+// This class listens to device motion data and dispatches it to all
+// listening controllers.
+class DeviceMotionDispatcher : public WebKit::WebDeviceMotionListener {
+public:
+    static DeviceMotionDispatcher& instance();
+
+    void addController(DeviceMotionController*);
+    void removeController(DeviceMotionController*);
+
+    // Note that the returned object is owned by this class.
+    // FIXME: make the return value const, see crbug.com/233174.
+    DeviceMotionData* latestDeviceMotionData();
+
+    // This method is called every time new device motion data is available.
+    virtual void didChangeDeviceMotion(const WebKit::WebDeviceMotionData&) OVERRIDE;
+
+private:
+    DeviceMotionDispatcher();
+    ~DeviceMotionDispatcher();
+
+    void startListening();
+    void stopListening();
+
+    void purgeControllers();
+
+    RefPtr<DeviceMotionData> m_lastDeviceMotionData;
+    Vector<DeviceMotionController*> m_controllers;
+};
+
+} // namespace WebCore
+
+#endif // DeviceMotionDispatcher_h