Hanohano Room   After an express glass-elevator ride up to the 30th floor of the Sheraton Waikiki hotel, you step into sophisticated, understated surroundings, enhanced with windows that reveal expansive views from Diamond Head all the way out to Ewa. Updated with accents of blue and a bar dubbed the Cobalt Lounge after dinner hours, the Hanohano Room remains a classic setting for special-occasion dinners, as the sun sets or by candlelight. The continental fare infused with Island touches includes such dishes as escargots in garlic-herb butter, wilted spinach salad prepared tableside, and flavorful stuffed tournedos of beef. Flambeed desserts are in keeping with the service-intensive vibe that keeps diners feeling pampered. Piano accompaniment and occasional live jazz provide the musical backdrop.  Sheraton Waikiki, 2255 Kalakaua Ave. 922-4422. 5:30-9 p.m. daily. Bar: 5-11:30 p.m. Reservations recommended. Valet and self-parking. AX, DC, DS, JCB, MC,VS. Checks accepted. $$$$.  Web site: www.sheratonwaikiki.com