Add optional visualization file writers to VideoProcessor tests.

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 9846fbcfdef20535e46e80efe5c3f3fe94ddc8e6..efc60c10d7b3f19fafacfaee8eafa4352c2173f6 100644
--- a/webrtc/modules/video_coding/codecs/test/videoprocessor_unittest.cc
+++ b/webrtc/modules/video_coding/codecs/test/videoprocessor_unittest.cc
@@ -69,7 +69,9 @@ TEST_F(VideoProcessorTest, Init) {
   ExpectInit();
   VideoProcessorImpl video_processor(
       &encoder_mock_, &decoder_mock_, &frame_reader_mock_, &frame_writer_mock_,
-      &packet_manipulator_mock_, config_, &stats_);
+      &packet_manipulator_mock_, config_, &stats_,
+      nullptr /* source_frame_writer */, nullptr /* encoded_frame_writer */,
+      nullptr /* decoded_frame_writer */);
   ASSERT_TRUE(video_processor.Init());
 }
 
@@ -82,7 +84,9 @@ TEST_F(VideoProcessorTest, ProcessFrame) {
   // be more than initialized...
   VideoProcessorImpl video_processor(
       &encoder_mock_, &decoder_mock_, &frame_reader_mock_, &frame_writer_mock_,
-      &packet_manipulator_mock_, config_, &stats_);
+      &packet_manipulator_mock_, config_, &stats_,
+      nullptr /* source_frame_writer */, nullptr /* encoded_frame_writer */,
+      nullptr /* decoded_frame_writer */);
   ASSERT_TRUE(video_processor.Init());
   video_processor.ProcessFrame(0);
 }