Merge "Removes existing singleInstance Activity when starts as home" into main

        // Get top task at beginning because the order may be changed when reusing existing task.

        final Task prevTopRootTask = mPreferredTaskDisplayArea.getFocusedRootTask();

        final Task prevTopTask = prevTopRootTask != null ? prevTopRootTask.getTopLeafTask() : null;

        final Task reusedTask = getReusableTask();

        final Task reusedTask = resolveReusableTask();

        // If requested, freeze the task list

        if (mOptions != null && mOptions.freezeRecentTasksReordering()

     * Decide whether the new activity should be inserted into an existing task. Returns null

     * if not or an ActivityRecord with the task into which the new activity should be added.

     */

    private Task getReusableTask() {

    private Task resolveReusableTask() {

        // If a target task is specified, try to reuse that one

        if (mOptions != null && mOptions.getLaunchTaskId() != INVALID_TASK_ID) {

            Task launchTask = mRootWindowContainer.anyTaskForId(mOptions.getLaunchTaskId());

                // There can be one and only one instance of single instance activity in the

                // history, and it is always in its own unique task, so we do a special search.

                intentActivity = mRootWindowContainer.findActivity(mIntent, mStartActivity.info,

                       mStartActivity.isActivityTypeHome());

                       false /* compareIntentFilters */);

                // Removes the existing singleInstance Activity if we're starting it as home

                // activity, while the existing one is not.

                if (intentActivity != null && mStartActivity.isActivityTypeHome()

                        && !intentActivity.isActivityTypeHome()) {

                    intentActivity.destroyIfPossible("Removes redundant singleInstance");

                    intentActivity = null;

                }

            } else if ((mLaunchFlags & FLAG_ACTIVITY_LAUNCH_ADJACENT) != 0) {

                // For the launch adjacent case we only want to put the activity in an existing

                // task if the activity already exists in the history.