DecoderBuffer: remove unused method _is_full()

src/decoder/DecoderBuffer.cxx

@@ -75,12 +75,6 @@ decoder_buffer_get_stream(const DecoderBuffer *buffer)
 	return *buffer->is;
 }
 
-bool
-decoder_buffer_is_full(const DecoderBuffer *buffer)
-{
-	return buffer->consumed == 0 && buffer->length == buffer->size;
-}
-
 void
 decoder_buffer_clear(DecoderBuffer *buffer)
 {

src/decoder/DecoderBuffer.hxx

@@ -58,10 +58,6 @@ gcc_pure
 const InputStream &
 decoder_buffer_get_stream(const DecoderBuffer *buffer);
 
-gcc_pure
-bool
-decoder_buffer_is_full(const DecoderBuffer *buffer);
-
 void
 decoder_buffer_clear(DecoderBuffer *buffer);