am 5b94ec47: [ActivityManager] Avoid mistaking visibility by finishing task.

            boolean startIt = true;

            for (int taskNdx = mTaskHistory.size() - 1; taskNdx >= 0; --taskNdx) {

                task = mTaskHistory.get(taskNdx);

                if (task.getTopActivity() == null) {

                    // All activities in task are finishing.

                    continue;

                }

                if (task == r.task) {

                    // Here it is!  Now, if this is not yet visible to the

                    // user, then just add it without starting; it will