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

webrtc/video/video_send_stream_tests.cc

 /*
  *  Copyright (c) 2013 The WebRTC project authors. All Rights Reserved.
  *
  *  Use of this source code is governed by a BSD-style license
  *  that can be found in the LICENSE file in the root of the source
  *  tree. An additional intellectual property rights grant can be found
  *  in the file PATENTS.  All contributing project authors may
  *  be found in the AUTHORS file in the root of the source tree.
  */
 #include <algorithm>  // max
@@ skipping 194 matching lines @@
       EXPECT_TRUE(Wait()) << "Timed out while waiting for a single RTP packet.";
     }
 
     test::DelayedEncoder encoder_;
   } test;
 
   RunBaseTest(&test);
 }
 
 TEST_F(VideoSendStreamTest, SupportsTransportWideSequenceNumbers) {
-  static const uint8_t kExtensionId = 13;
+  static const uint8_t kExtensionId = test::kTransportSequenceNumberExtensionId;
   class TransportWideSequenceNumberObserver : public test::SendTest {
    public:
     TransportWideSequenceNumberObserver()
         : SendTest(kDefaultTimeoutMs), encoder_(Clock::GetRealTimeClock()) {
       EXPECT_TRUE(parser_->RegisterRtpHeaderExtension(
           kRtpExtensionTransportSequenceNumber, kExtensionId));
     }
 
    private:
     Action OnSendRtp(const uint8_t* packet, size_t length) override {
@@ skipping 982 matching lines @@
     VideoSendStream* stream_;
     bool bitrate_capped_;
   } test;
 
   RunBaseTest(&test);
 }
 
 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()
         : EndToEndTest(test::CallTest::kDefaultTimeoutMs), call_(nullptr) {
       EXPECT_TRUE(parser_->RegisterRtpHeaderExtension(
           kRtpExtensionTransportSequenceNumber, kExtensionId));
     }
 
     void OnCallsCreated(Call* sender_call, Call* receiver_call) override {
       call_ = sender_call;
@@ skipping 1659 matching lines @@
         observation_complete_.Set();
       }
     }
   } test;
 
   RunBaseTest(&test);
 }
 #endif  // !defined(RTC_DISABLE_VP9)
 
 }  // namespace webrtc