Ensure one does not register same rtp header extension with different id

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 9d00e007de2f15427e1e3c0c07f13e27c3f40709..16a42471527869e1934499095e9829aea0a67b87 100644
--- a/webrtc/video/video_send_stream_tests.cc
+++ b/webrtc/video/video_send_stream_tests.cc
@@ -212,7 +212,7 @@ TEST_F(VideoSendStreamTest, SupportsTransmissionTimeOffset) {
 }
 
 TEST_F(VideoSendStreamTest, SupportsTransportWideSequenceNumbers) {
-  static const uint8_t kExtensionId = 13;
+  static const uint8_t kExtensionId = test::kTransportSequenceNumberExtensionId;
   class TransportWideSequenceNumberObserver : public test::SendTest {
    public:
     TransportWideSequenceNumberObserver()
@@ -1215,7 +1215,7 @@ TEST_F(VideoSendStreamTest, MinTransmitBitrateRespectsRemb) {
 TEST_F(VideoSendStreamTest, ChangingNetworkRoute) {
   static const int kStartBitrateBps = 300000;
   static const int kNewMaxBitrateBps = 1234567;
-  static const uint8_t kExtensionId = 13;
+  static const uint8_t kExtensionId = test::kTransportSequenceNumberExtensionId;
   class ChangingNetworkRouteTest : public test::EndToEndTest {
    public:
     ChangingNetworkRouteTest()