decoder/Client: use std::chrono::duration<double> instead of raw double

src/decoder/Bridge.hxx

@@ -49,7 +49,7 @@ public:
 	/**
 	 * The time stamp of the next data chunk, in seconds.
 	 */
-	double timestamp = 0;
+	FloatDuration timestamp = FloatDuration::zero();
 
 	/**
 	 * The time stamp of the next data chunk, in PCM frames.
@@ -148,7 +148,7 @@ public:
 	void SeekError() override;
 	InputStreamPtr OpenUri(const char *uri) override;
 	size_t Read(InputStream &is, void *buffer, size_t length) override;
-	void SubmitTimestamp(double t) override;
+	void SubmitTimestamp(FloatDuration t) override;
 	DecoderCommand SubmitData(InputStream *is,
 				  const void *data, size_t length,
 				  uint16_t kbit_rate) override;