libcamera: software_isp: Track and pass frame ids

A previous preparation patch implemented passing frame ids to stats
processing but without actual meaningful frame id value passed there.
This patch extends that by actually providing the frame id and passing
it through to the stats processor.

The frame id is taken from the request sequence number, the same as in
hardware pipelines.

Signed-off-by: Milan Zamazal <mzamazal@redhat.com>
Reviewed-by: Daniel Scally <dan.scally@ideasonboard.com>
Reviewed-by: Kieran Bingham <kieran.bingham@ideasonboard.com>
Signed-off-by: Kieran Bingham <kieran.bingham@ideasonboard.com>

src/libcamera/pipeline/simple/simple.cpp

@@ -861,7 +861,13 @@ void SimpleCameraData::bufferReady(FrameBuffer *buffer)
 		if (converter_)
 			converter_->queueBuffers(buffer, conversionQueue_.front());
 		else
-			swIsp_->queueBuffers(buffer, conversionQueue_.front());
+			/*
+			 * request->sequence() cannot be retrieved from `buffer' inside
+			 * queueBuffers because unique_ptr's make buffer->request() invalid
+			 * already here.
+			 */
+			swIsp_->queueBuffers(request->sequence(), buffer,
+					     conversionQueue_.front());
 
 		conversionQueue_.pop();
 		return;