Fix SecurityException when exiting wallpaper picker early

        final Context context = this;

        new AsyncTask<Void, Bitmap, Bitmap>() {

            protected Bitmap doInBackground(Void...args) {

                try {

                    int rotation = WallpaperCropActivity.getRotationFromExif(context, uri);

                    return createThumbnail(defaultSize, context, uri, null, null, 0, rotation, false);

                } catch (SecurityException securityException) {

                    if (isDestroyed()) {

                        // Temporarily granted permissions are revoked when the activity

                        // finishes, potentially resulting in a SecurityException here.

                        // Even though {@link #isDestroyed} might also return true in different

                        // situations where the configuration changes, we are fine with

                        // catching these cases here as well.

                        cancel(false);

                    } else {

                        // otherwise it had a different cause and we throw it further

                        throw securityException;

                    }

                    return null;

                }

            }

            protected void onPostExecute(Bitmap thumb) {

                if (thumb != null) {

                if (!isCancelled() && thumb != null) {

                    image.setImageBitmap(thumb);

                    Drawable thumbDrawable = image.getDrawable();

                    thumbDrawable.setDither(true);