As Dan Bron says, "until the shine wears off" is an idiom that normally means "until the thing in question loses its novelty or freshness."
The first instance of "shine wears off" that a Google Books search finds is from Elizabeth Stuart Phelps, "In the Gray Goth" in Atlantic Monthly (November 1867):
I tell you, Johnny, young folks they start in life with very pretty ideas,—very pretty. But take it as a general thing, they don't know any more what they're talking about than they do about each other, and they don't know any more about each other than they do about the man in the moon. They begin very nice, with their new carpets and teaspoons, and a little mending to do, and coming home early evenings to talk ; but by and by the shine wears off. Then come the babies, and worry and wear and temper. About that time they begin to be a little acquainted, and to find out that there are two wills and two sets of habits to be fitted somehow. It takes them anywhere along from one year to three to get jostled down together. As for smoothing off, there's more or less of that to be done always.
In this example from almost 150 years ago, the shine appears to wear off the teaspoons and (metaphorically) everything else pretty quickly—before the babies arrive, even. But in the Coldplay song, I don't know what the still-shining thing is whose dimming the singer awaits. Life, maybe?