Fix timing frames and FEC conflict

webrtc/video/video_send_stream_tests.cc

Index: webrtc/video/video_send_stream_tests.cc
diff --git a/webrtc/video/video_send_stream_tests.cc b/webrtc/video/video_send_stream_tests.cc
index db1ba4f49014308a01b223958bce9b62db6f52ed..d0c4fd0da9c7ad9d5a1633df32a1e4d0ef3f849b 100644
--- a/webrtc/video/video_send_stream_tests.cc
+++ b/webrtc/video/video_send_stream_tests.cc
@@ -348,9 +348,11 @@ TEST_F(VideoSendStreamTest, SupportsVideoTimingFrames) {
     Action OnSendRtp(const uint8_t* packet, size_t length) override {
       RTPHeader header;
       EXPECT_TRUE(parser_->Parse(packet, length, &header));
-      if (header.extension.has_video_timing) {
-        observation_complete_.Set();
-      }
+      // Only the last packet of the frame must have extension.
+      if (!header.markerBit)
+        return SEND_PACKET;
+      EXPECT_TRUE(header.extension.has_video_timing);
+      observation_complete_.Set();
       return SEND_PACKET;
     }