In a large skillet, melt butter, and saute onion until transparent. Add chicken, chicken broth, celery, potatoes, and the bay leaf. Bring to boil. Reduce heat and simmer 1 hour, or until the vegetables are tender. Add liquid if necessary. Stir in the corn, the soup and the heavy cream and sugar. For a thicker chowder, slowly add 1/2 cup flour mixed with warm water. Cook another 20 minutes, stirring occasionally.