ReplayGainInfo: implement fallback in Get()

Eliminates Complete().

src/ReplayGainInfo.cxx

@@ -41,10 +41,3 @@ ReplayGainTuple::CalculateScale(float preamp, float missing_preamp,
 
 	return scale;
 }
-
-void
-ReplayGainInfo::Complete()
-{
-	if (!tuples[REPLAY_GAIN_ALBUM].IsDefined())
-		tuples[REPLAY_GAIN_ALBUM] = tuples[REPLAY_GAIN_TRACK];
-}

src/ReplayGainInfo.hxx

@@ -57,19 +57,19 @@ struct ReplayGainInfo {
 	}
 
 	const ReplayGainTuple &Get(ReplayGainMode mode) const {
-		return tuples[mode];
+		return mode == REPLAY_GAIN_ALBUM
+			? (tuples[REPLAY_GAIN_ALBUM].IsDefined()
+			   ? tuples[REPLAY_GAIN_ALBUM]
+			   : tuples[REPLAY_GAIN_TRACK])
+			: (tuples[REPLAY_GAIN_TRACK].IsDefined()
+			   ? tuples[REPLAY_GAIN_TRACK]
+			   : tuples[REPLAY_GAIN_ALBUM]);
 	}
 
 	void Clear() {
 		tuples[REPLAY_GAIN_ALBUM].Clear();
 		tuples[REPLAY_GAIN_TRACK].Clear();
 	}
-
-	/**
-	 * Attempt to auto-complete missing data.  In particular, if
-	 * album information is missing, track gain is used.
-	 */
-	void Complete();
 };
 
 #endif

src/filter/plugins/ReplayGainFilterPlugin.cxx

@@ -79,10 +79,9 @@ public:
 	}
 
 	void SetInfo(const ReplayGainInfo *_info) {
-		if (_info != nullptr) {
+		if (_info != nullptr)
 			info = *_info;
-			info.Complete();
-		} else
+		else
 			info.Clear();
 
 		Update();