Allow multiple calls to ProcessFramesAndMaybeVerify with frame writers enabled.

Bug: None
Change-Id: Ic6e52401ec2db3d0bcaca3605c28763123a4eeb8
Reviewed-on: https://webrtc-review.googlesource.com/72343
Reviewed-by: Sergey Silkin <ssilkin@webrtc.org>
Commit-Queue: Rasmus Brandt <brandtr@webrtc.org>
Cr-Commit-Position: refs/heads/master@{#23016}
diff --git a/modules/video_coding/codecs/test/videoprocessor_integrationtest.cc b/modules/video_coding/codecs/test/videoprocessor_integrationtest.cc
index 12edc8a..3079ed3 100644
--- a/modules/video_coding/codecs/test/videoprocessor_integrationtest.cc
+++ b/modules/video_coding/codecs/test/videoprocessor_integrationtest.cc
@@ -394,6 +394,8 @@
       config_.NumberOfSimulcastStreams(), config_.NumberOfSpatialLayers());
 
   if (visualization_params) {
+    RTC_DCHECK(encoded_frame_writers_.empty());
+    RTC_DCHECK(decoded_frame_writers_.empty());
     for (size_t simulcast_svc_idx = 0;
          simulcast_svc_idx < num_simulcast_or_spatial_layers;
          ++simulcast_svc_idx) {
@@ -453,9 +455,11 @@
   for (auto& encoded_frame_writer : encoded_frame_writers_) {
     EXPECT_TRUE(encoded_frame_writer->Close());
   }
+  encoded_frame_writers_.clear();
   for (auto& decoded_frame_writer : decoded_frame_writers_) {
     decoded_frame_writer->Close();
   }
+  decoded_frame_writers_.clear();
 }
 
 void VideoProcessorIntegrationTest::PrintSettings(