--- a/media/webrtc/signaling/gtest/jsep_session_unittest.cpp
+++ b/media/webrtc/signaling/gtest/jsep_session_unittest.cpp
@@ -4291,44 +4291,47 @@ TEST_F(JsepSessionTest, TestExtmap)
   SetRemoteAnswer(answer, CHECK_SUCCESS);
 
   UniquePtr<Sdp> parsedOffer(Parse(offer));
   ASSERT_EQ(1U, parsedOffer->GetMediaSectionCount());
 
   auto& offerMediaAttrs = parsedOffer->GetMediaSection(0).GetAttributeList();
   ASSERT_TRUE(offerMediaAttrs.HasAttribute(SdpAttribute::kExtmapAttribute));
   auto& offerExtmap = offerMediaAttrs.GetExtmap().mExtmaps;
-  ASSERT_EQ(4U, offerExtmap.size());
+  ASSERT_EQ(5U, offerExtmap.size());
   ASSERT_EQ("urn:ietf:params:rtp-hdrext:ssrc-audio-level",
       offerExtmap[0].extensionname);
   ASSERT_EQ(1U, offerExtmap[0].entry);
-  ASSERT_EQ("urn:ietf:params:rtp-hdrext:sdes:mid",
+  ASSERT_EQ("urn:ietf:params:rtp-hdrext:csrc-audio-level",
       offerExtmap[1].extensionname);
   ASSERT_EQ(2U, offerExtmap[1].entry);
-  ASSERT_EQ("foo", offerExtmap[2].extensionname);
+  ASSERT_EQ("urn:ietf:params:rtp-hdrext:sdes:mid",
+      offerExtmap[2].extensionname);
   ASSERT_EQ(3U, offerExtmap[2].entry);
-  ASSERT_EQ("bar", offerExtmap[3].extensionname);
+  ASSERT_EQ("foo", offerExtmap[3].extensionname);
   ASSERT_EQ(4U, offerExtmap[3].entry);
+  ASSERT_EQ("bar", offerExtmap[4].extensionname);
+  ASSERT_EQ(5U, offerExtmap[4].entry);
 
   UniquePtr<Sdp> parsedAnswer(Parse(answer));
   ASSERT_EQ(1U, parsedAnswer->GetMediaSectionCount());
 
   auto& answerMediaAttrs = parsedAnswer->GetMediaSection(0).GetAttributeList();
   ASSERT_TRUE(answerMediaAttrs.HasAttribute(SdpAttribute::kExtmapAttribute));
   auto& answerExtmap = answerMediaAttrs.GetExtmap().mExtmaps;
   ASSERT_EQ(3U, answerExtmap.size());
   ASSERT_EQ("urn:ietf:params:rtp-hdrext:ssrc-audio-level",
       offerExtmap[0].extensionname);
   ASSERT_EQ(1U, offerExtmap[0].entry);
   ASSERT_EQ("urn:ietf:params:rtp-hdrext:sdes:mid",
       answerExtmap[1].extensionname);
   ASSERT_EQ(2U, offerExtmap[1].entry);
   // We ensure that the entry for "bar" matches what was in the offer
   ASSERT_EQ("bar", answerExtmap[2].extensionname);
-  ASSERT_EQ(4U, answerExtmap[2].entry);
+  ASSERT_EQ(5U, answerExtmap[2].entry);
 }
 
 TEST_F(JsepSessionTest, TestExtmapWithDuplicates)
 {
   AddTracks(*mSessionOff, "audio");
   AddTracks(*mSessionAns, "audio");
   // ssrc-audio-level will be extmap 1 for both
   mSessionOff->AddAudioRtpExtension("foo"); // Default mapping of 3
@@ -4340,29 +4343,32 @@ TEST_F(JsepSessionTest, TestExtmapWithDu
 
   std::string offer = CreateOffer();
   UniquePtr<Sdp> parsedOffer(Parse(offer));
   ASSERT_EQ(1U, parsedOffer->GetMediaSectionCount());
 
   auto& offerMediaAttrs = parsedOffer->GetMediaSection(0).GetAttributeList();
   ASSERT_TRUE(offerMediaAttrs.HasAttribute(SdpAttribute::kExtmapAttribute));
   auto& offerExtmap = offerMediaAttrs.GetExtmap().mExtmaps;
-  ASSERT_EQ(5U, offerExtmap.size());
+  ASSERT_EQ(6U, offerExtmap.size());
   ASSERT_EQ("urn:ietf:params:rtp-hdrext:ssrc-audio-level",
       offerExtmap[0].extensionname);
   ASSERT_EQ(1U, offerExtmap[0].entry);
-  ASSERT_EQ("urn:ietf:params:rtp-hdrext:sdes:mid",
+  ASSERT_EQ("urn:ietf:params:rtp-hdrext:csrc-audio-level",
       offerExtmap[1].extensionname);
   ASSERT_EQ(2U, offerExtmap[1].entry);
-  ASSERT_EQ("foo", offerExtmap[2].extensionname);
+  ASSERT_EQ("urn:ietf:params:rtp-hdrext:sdes:mid",
+      offerExtmap[2].extensionname);
   ASSERT_EQ(3U, offerExtmap[2].entry);
-  ASSERT_EQ("bar", offerExtmap[3].extensionname);
+  ASSERT_EQ("foo", offerExtmap[3].extensionname);
   ASSERT_EQ(4U, offerExtmap[3].entry);
-  ASSERT_EQ("baz", offerExtmap[4].extensionname);
+  ASSERT_EQ("bar", offerExtmap[4].extensionname);
   ASSERT_EQ(5U, offerExtmap[4].entry);
+  ASSERT_EQ("baz", offerExtmap[5].extensionname);
+  ASSERT_EQ(6U, offerExtmap[5].entry);
 }
 
 
 TEST_F(JsepSessionTest, TestRtcpFbStar)
 {
   AddTracks(*mSessionOff, "video");
   AddTracks(*mSessionAns, "video");