My HDD is partitioned into two equal sized partitions. First is being used for Windows and Second for Ubuntu. Everything is working fine. But now I want to remove Windows and use the disk completely for Ubuntu. I can easily boot from live cd and use GParted to delete Windows partition and then expand Ubuntu partition to use the whole hard disk. But I want to know if its safe i.e Will resizing Ubuntu partition change any thing else like the partition UUID or any thing else? Do I need to reinstall grub after resizing the root partition?

It would be great if some one who has already done this can give their advice here.