Set protected_by_flexfec flag properly in tests.

video/video_quality_test.cc

Index: video/video_quality_test.cc
diff --git a/video/video_quality_test.cc b/video/video_quality_test.cc
index 16b3f65cd3787c9bb70c32cf404e58c51bb49e61..ef04725e3ca98b9e44333faf8e6a1ed48dd93df3 100644
--- a/video/video_quality_test.cc
+++ b/video/video_quality_test.cc
@@ -1539,6 +1539,9 @@ void VideoQualityTest::SetupVideo(Transport* send_transport,
           RtpExtension::kAbsSendTimeUri, test::kAbsSendTimeExtensionId));
     }
     flexfec_receive_configs_.push_back(flexfec_receive_config);
+    if (num_video_streams > 0) {
+      video_receive_configs_[0].rtp.protected_by_flexfec = true;
+    }
   }
 
   if (params_.video.ulpfec) {