android: post_processor: Drop return value for process()

PostProcessor::process() is invoked by CameraStream class
in case any post-processing is required for the camera stream.
The failure or success is checked via the value returned by
CameraStream::process().

Now that the post-processor notifies about the post-processing
completion operation, we can drop the return value of
PostProcessor::process(). The status of post-processing is passed
to CameraDevice::streamProcessingComplete() by the
PostProcessor::processComplete signal's slot.

Signed-off-by: Umang Jain <umang.jain@ideasonboard.com>
Reviewed-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Reviewed-by: Hirokazu Honda <hiroh@chromium.org>

src/android/camera_stream.cpp

@@ -191,7 +191,9 @@ int CameraStream::process(Camera3RequestDescriptor::StreamBuffer *streamBuffer)
 		return -EINVAL;
 	}
 
-	return postProcessor_->process(streamBuffer);
+	postProcessor_->process(streamBuffer);
+
+	return 0;
 }
 
 FrameBuffer *CameraStream::getBuffer()