Merge "Fix thread safety issues;"

    @Retention(RetentionPolicy.SOURCE)

    public @interface ScreenState {}

    private @ScreenState int mScreenState = SCREEN_STATE_UNKNOWN;

    private Long mLastChanged = null;

    private volatile @ScreenState int mScreenState = SCREEN_STATE_UNKNOWN;

    private volatile Long mLastChanged = null;

    private static final int LOG_SUBTYPE_UNFOLDED = 0;

    private static final int LOG_SUBTYPE_FOLDED = 1;