Merge "Guard against SecurityException of accessing to slice uri" into rvc-dev

        // Workaround of unpinning slice in the same SerialExecutor of AsyncTask as SliceCallback's

        // observer.

        ThreadUtils.postOnMainThread(() ->

                AsyncTask.execute(() -> manager.unregisterSliceCallback(uri, callback))

        );

        ThreadUtils.postOnMainThread(() -> AsyncTask.execute(() -> {

            try {

                manager.unregisterSliceCallback(uri, callback);

            } catch (SecurityException e) {

                Log.d(TAG, "No permission currently: " + e);

            }

        }));

        return slice;

    }