Fix crash with animation specs

        // This is used by freeform <-> recents windows transition. We need to synchronize

        // the animation with the appearance of the content of recents, so we will make

        // animation stay on the first or last frame a little longer.

        if (specs == null) {

            Slog.wtf(TAG, "prolongAnimationsFromSpecs: AppTransitionAnimationSpec is null!");

            return;

        }

        mTmpTaskIds.clear();

        for (int i = specs.length - 1; i >= 0; i--) {

            mTmpTaskIds.put(specs[i].taskId, 0);