RTCRTPStreamStats.mediaTrackId renamed to trackId.

According to spec change:
https://github.com/w3c/webrtc-stats/pull/142

BUG=webrtc:7064, chromium:685655

Review-Url: https://codereview.webrtc.org/2619353007
Cr-Commit-Position: refs/heads/master@{#16326}
diff --git a/webrtc/api/stats/rtcstats_objects.h b/webrtc/api/stats/rtcstats_objects.h
index 760ec9e..c5277e7 100644
--- a/webrtc/api/stats/rtcstats_objects.h
+++ b/webrtc/api/stats/rtcstats_objects.h
@@ -312,7 +312,7 @@
   // crbug.com/657855, 657856
   RTCStatsMember<bool> is_remote;  // = false
   RTCStatsMember<std::string> media_type;
-  RTCStatsMember<std::string> media_track_id;
+  RTCStatsMember<std::string> track_id;
   RTCStatsMember<std::string> transport_id;
   RTCStatsMember<std::string> codec_id;
   // FIR and PLI counts are only defined for |media_type == "video"|.
diff --git a/webrtc/pc/rtcstats_integrationtest.cc b/webrtc/pc/rtcstats_integrationtest.cc
index 0765276..5775047 100644
--- a/webrtc/pc/rtcstats_integrationtest.cc
+++ b/webrtc/pc/rtcstats_integrationtest.cc
@@ -505,7 +505,7 @@
     verifier->TestMemberIsDefined(stream.is_remote);
     verifier->TestMemberIsDefined(stream.media_type);
     verifier->TestMemberIsIDReference(
-        stream.media_track_id, RTCMediaStreamTrackStats::kType);
+        stream.track_id, RTCMediaStreamTrackStats::kType);
     verifier->TestMemberIsIDReference(
         stream.transport_id, RTCTransportStats::kType);
     verifier->TestMemberIsIDReference(stream.codec_id, RTCCodecStats::kType);
diff --git a/webrtc/pc/rtcstatscollector.cc b/webrtc/pc/rtcstatscollector.cc
index 774d1d7..6344d87 100644
--- a/webrtc/pc/rtcstatscollector.cc
+++ b/webrtc/pc/rtcstatscollector.cc
@@ -930,7 +930,7 @@
           track_media_info_map_->GetAudioTrack(voice_receiver_info);
       if (audio_track) {
         RTC_DCHECK(track_to_id_.find(audio_track.get()) != track_to_id_.end());
-        inbound_audio->media_track_id =
+        inbound_audio->track_id =
             RTCMediaStreamTrackStatsIDFromTrackKindIDAndSsrc(
                 false,
                 MediaStreamTrackInterface::kAudioKind,
@@ -963,7 +963,7 @@
           track_media_info_map_->GetAudioTrack(voice_sender_info);
       if (audio_track) {
         RTC_DCHECK(track_to_id_.find(audio_track.get()) != track_to_id_.end());
-        outbound_audio->media_track_id =
+        outbound_audio->track_id =
             RTCMediaStreamTrackStatsIDFromTrackKindIDAndSsrc(
                 true,
                 MediaStreamTrackInterface::kAudioKind,
@@ -1002,7 +1002,7 @@
           track_media_info_map_->GetVideoTrack(video_receiver_info);
       if (video_track) {
         RTC_DCHECK(track_to_id_.find(video_track.get()) != track_to_id_.end());
-        inbound_video->media_track_id =
+        inbound_video->track_id =
             RTCMediaStreamTrackStatsIDFromTrackKindIDAndSsrc(
                 false,
                 MediaStreamTrackInterface::kVideoKind,
@@ -1035,7 +1035,7 @@
           track_media_info_map_->GetVideoTrack(video_sender_info);
       if (video_track) {
         RTC_DCHECK(track_to_id_.find(video_track.get()) != track_to_id_.end());
-        outbound_video->media_track_id =
+        outbound_video->track_id =
             RTCMediaStreamTrackStatsIDFromTrackKindIDAndSsrc(
                 true,
                 MediaStreamTrackInterface::kVideoKind,
diff --git a/webrtc/pc/rtcstatscollector_unittest.cc b/webrtc/pc/rtcstatscollector_unittest.cc
index d6dbffb..6d1595e 100644
--- a/webrtc/pc/rtcstatscollector_unittest.cc
+++ b/webrtc/pc/rtcstatscollector_unittest.cc
@@ -1720,7 +1720,7 @@
   expected_audio.ssrc = "1";
   expected_audio.is_remote = false;
   expected_audio.media_type = "audio";
-  expected_audio.media_track_id =
+  expected_audio.track_id =
       "RTCMediaStreamTrack_remote_audio_RemoteAudioTrackID_1";
   expected_audio.transport_id = "RTCTransport_TransportName_" +
       rtc::ToString<>(cricket::ICE_CANDIDATE_COMPONENT_RTP);
@@ -1736,7 +1736,7 @@
       expected_audio.id())->cast_to<RTCInboundRTPStreamStats>();
   EXPECT_EQ(audio, expected_audio);
 
-  EXPECT_TRUE(report->Get(*expected_audio.media_track_id));
+  EXPECT_TRUE(report->Get(*expected_audio.track_id));
   EXPECT_TRUE(report->Get(*expected_audio.transport_id));
   EXPECT_TRUE(report->Get(*expected_audio.codec_id));
 }
@@ -1802,7 +1802,7 @@
   expected_video.ssrc = "1";
   expected_video.is_remote = false;
   expected_video.media_type = "video";
-  expected_video.media_track_id =
+  expected_video.track_id =
       "RTCMediaStreamTrack_remote_video_RemoteVideoTrackID_1";
   expected_video.transport_id = "RTCTransport_TransportName_" +
       rtc::ToString<>(cricket::ICE_CANDIDATE_COMPONENT_RTP);
@@ -1821,7 +1821,7 @@
       expected_video.id())->cast_to<RTCInboundRTPStreamStats>();
   EXPECT_EQ(video, expected_video);
 
-  EXPECT_TRUE(report->Get(*expected_video.media_track_id));
+  EXPECT_TRUE(report->Get(*expected_video.track_id));
   EXPECT_TRUE(report->Get(*expected_video.transport_id));
   EXPECT_TRUE(report->Get(*video.codec_id));
 }
@@ -1881,7 +1881,7 @@
   expected_audio.ssrc = "1";
   expected_audio.is_remote = false;
   expected_audio.media_type = "audio";
-  expected_audio.media_track_id =
+  expected_audio.track_id =
       "RTCMediaStreamTrack_local_audio_LocalAudioTrackID_1";
   expected_audio.transport_id = "RTCTransport_TransportName_" +
       rtc::ToString<>(cricket::ICE_CANDIDATE_COMPONENT_RTP);
@@ -1895,7 +1895,7 @@
       expected_audio.id())->cast_to<RTCOutboundRTPStreamStats>();
   EXPECT_EQ(audio, expected_audio);
 
-  EXPECT_TRUE(report->Get(*expected_audio.media_track_id));
+  EXPECT_TRUE(report->Get(*expected_audio.track_id));
   EXPECT_TRUE(report->Get(*expected_audio.transport_id));
   EXPECT_TRUE(report->Get(*expected_audio.codec_id));
 }
@@ -1960,7 +1960,7 @@
   expected_video.ssrc = "1";
   expected_video.is_remote = false;
   expected_video.media_type = "video";
-  expected_video.media_track_id =
+  expected_video.track_id =
       "RTCMediaStreamTrack_local_video_LocalVideoTrackID_1";
   expected_video.transport_id = "RTCTransport_TransportName_" +
       rtc::ToString<>(cricket::ICE_CANDIDATE_COMPONENT_RTP);
@@ -1979,7 +1979,7 @@
       expected_video.id())->cast_to<RTCOutboundRTPStreamStats>();
   EXPECT_EQ(video, expected_video);
 
-  EXPECT_TRUE(report->Get(*expected_video.media_track_id));
+  EXPECT_TRUE(report->Get(*expected_video.track_id));
   EXPECT_TRUE(report->Get(*expected_video.transport_id));
   EXPECT_TRUE(report->Get(*expected_video.codec_id));
 }
diff --git a/webrtc/stats/rtcstats_objects.cc b/webrtc/stats/rtcstats_objects.cc
index af87e71..68b33f5 100644
--- a/webrtc/stats/rtcstats_objects.cc
+++ b/webrtc/stats/rtcstats_objects.cc
@@ -455,7 +455,7 @@
     &associate_stats_id,
     &is_remote,
     &media_type,
-    &media_track_id,
+    &track_id,
     &transport_id,
     &codec_id,
     &fir_count,
@@ -476,7 +476,7 @@
       associate_stats_id("associateStatsId"),
       is_remote("isRemote", false),
       media_type("mediaType"),
-      media_track_id("mediaTrackId"),
+      track_id("trackId"),
       transport_id("transportId"),
       codec_id("codecId"),
       fir_count("firCount"),
@@ -493,7 +493,7 @@
       associate_stats_id(other.associate_stats_id),
       is_remote(other.is_remote),
       media_type(other.media_type),
-      media_track_id(other.media_track_id),
+      track_id(other.track_id),
       transport_id(other.transport_id),
       codec_id(other.codec_id),
       fir_count(other.fir_count),