Heat water in saucepan, add salt and chicken; cover. Simmer (do not boil) 2½ to 3 hours or until the thigh meat is tender. Take meat from bones and cut into chunks.
Heat chicken broth with juice from mushrooms. Blend flour, garlic salt, pepper and cream. Stir into broth; cook, stirring constantly until thickened. Remove from heat. Stir in cheese.