Fix alpha value for device orientation

This seems to have been incorrect since this code was first written for HC. I
can only think that the error was made due to confusion between portrait and
landscape mode as development switched from phones to tablets.

Tested on stingray and prime.

A similar fix will be required for Chrome.

Change-Id: I5da13c489fdb9de340b9e6ea8868c9f1adc15bb2

core/java/android/webkit/DeviceOrientationService.java

@@ -123,7 +123,7 @@ final class DeviceOrientationService implements SensorEventListener {
         // The angles are in radians
         float[] rotationAngles = new float[3];
         SensorManager.getOrientation(deviceRotationMatrix, rotationAngles);
-        double alpha = Math.toDegrees(-rotationAngles[0]) - 90.0;
+        double alpha = Math.toDegrees(-rotationAngles[0]);
         while (alpha < 0.0) { alpha += 360.0; } // [0, 360)
         double beta = Math.toDegrees(-rotationAngles[1]);
         while (beta < -180.0) { beta += 360.0; } // [-180, 180)