Remove source file writer from VideoProcessor.

webrtc/modules/video_coding/codecs/test/videoprocessor_unittest.cc

Index: webrtc/modules/video_coding/codecs/test/videoprocessor_unittest.cc
diff --git a/webrtc/modules/video_coding/codecs/test/videoprocessor_unittest.cc b/webrtc/modules/video_coding/codecs/test/videoprocessor_unittest.cc
index 96e20377b956235ca457b7e9d979284bde9783b3..47e27d72f40ae604d8ab46f955c284aec34f14d7 100644
--- a/webrtc/modules/video_coding/codecs/test/videoprocessor_unittest.cc
+++ b/webrtc/modules/video_coding/codecs/test/videoprocessor_unittest.cc
@@ -59,8 +59,7 @@ class VideoProcessorTest : public testing::Test {
     video_processor_ = rtc::MakeUnique<VideoProcessor>(
         &encoder_mock_, &decoder_mock_, &frame_reader_mock_,
         &frame_writer_mock_, &packet_manipulator_mock_, config_, &stats_,
-        nullptr /* source_frame_writer */, nullptr /* encoded_frame_writer */,
-        nullptr /* decoded_frame_writer */);
+        nullptr /* encoded_frame_writer */, nullptr /* decoded_frame_writer */);
   }
 
   void ExpectInit() {