Merge "Removes the hidden tasks that exceeds the cache limit" into udc-qpr-dev

    /** The non-empty tasks that are removed from recent tasks (see {@link #removeForAddTask}). */

    private final ArrayList<Task> mHiddenTasks = new ArrayList<>();

    /** The maximum size that the hidden tasks are cached. */

    private static final int MAX_HIDDEN_TASK_SIZE = 10;

    /** Whether to trim inactive tasks when activities are idle. */

    private boolean mCheckTrimmableTasksOnIdle;

        return task.compareTo(rootHomeTask) < 0;

    }

    /** Remove the tasks that user may not be able to return. */

    /** Remove the tasks that user may not be able to return when exceeds the cache limit. */

    private void removeUnreachableHiddenTasks(int windowingMode) {

        for (int i = mHiddenTasks.size() - 1; i >= 0; i--) {

        final int size = mHiddenTasks.size();

        if (size <= MAX_HIDDEN_TASK_SIZE) {

            return;

        }

        for (int i = size - 1; i >= MAX_HIDDEN_TASK_SIZE; i--) {

            final Task hiddenTask = mHiddenTasks.get(i);

            if (!hiddenTask.hasChild() || hiddenTask.inRecents) {

                // The task was removed by other path or it became reachable (added to recents).

                // A non-empty task is replaced by a new task. Because the removed task is no longer

                // managed by the recent tasks list, add it to the hidden list to prevent the task

                // from becoming dangling.

                mHiddenTasks.add(removedTask);

                mHiddenTasks.add(0, removedTask);

            }

            notifyTaskRemoved(removedTask, false /* wasTrimmed */, false /* killProcess */);

            if (DEBUG_RECENTS_TRIM_TASKS) {