Merge "Camera2: partialResultCount should be optional" into lmp-dev

     * then immediately dispatch this state via a partial result to

     * the application, and the rest of the metadata via later

     * partial results.</p>

     * <p><b>Optional</b> - This value may be {@code null} on some devices.</p>

     */

    public static final Key<Integer> REQUEST_PARTIAL_RESULT_COUNT =

            new Key<Integer>("android.request.partialResultCount", int.class);