Implement the Blink part of the Device Motion API.

Source/modules/device_orientation/DeviceMotionData.h

Index: Source/modules/device_orientation/DeviceMotionData.h
diff --git a/Source/modules/device_orientation/DeviceMotionData.h b/Source/modules/device_orientation/DeviceMotionData.h
index d7ef0fd0efcf31a75530576f576bb39f98d52d69..3db267d2a21597b22cc6c74d5629b9b35ccfcf9c 100644
--- a/Source/modules/device_orientation/DeviceMotionData.h
+++ b/Source/modules/device_orientation/DeviceMotionData.h
@@ -30,6 +30,10 @@
 #include <wtf/RefCounted.h>
 #include <wtf/RefPtr.h>
 
+namespace WebKit {
+class WebDeviceMotionData;
+}
+
 namespace WebCore {
 
 class DeviceMotionData : public RefCounted<DeviceMotionData> {
@@ -85,6 +89,7 @@ public:
     static PassRefPtr<DeviceMotionData> create();
     static PassRefPtr<DeviceMotionData> create(PassRefPtr<Acceleration> acceleration, PassRefPtr<Acceleration> accelerationIncludingGravity,
                                                PassRefPtr<RotationRate> rotationRate, bool canProvideInterval, double interval);
+    static PassRefPtr<DeviceMotionData> create(const WebKit::WebDeviceMotionData&);
 
     PassRefPtr<Acceleration> acceleration() const { return m_acceleration; }
     PassRefPtr<Acceleration> accelerationIncludingGravity() const { return m_accelerationIncludingGravity; }