Fix getStats test for RTPReceiver

The test for getStats() on an RTP receiver was testing with the wrong
track (sent track not received track).
The change gives a reasonable error message (not all stats are present).

Bug: none
Change-Id: I7f35dc90a2e4f6ee4ed67e8d6ae2ecdf9246c2a3
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2060952Reviewed-by: Henrik Boström <hbos@chromium.org>
Commit-Queue: Harald Alvestrand <hta@chromium.org>
Cr-Commit-Position: refs/heads/master@{#742094}

third_party/blink/web_tests/external/wpt/webrtc/RTCPeerConnection-getStats.https-expected.txt

@@ -10,7 +10,7 @@ PASS getStats() with no argument should return stats report containing peer-conn
 FAIL getStats() with no argument should return stats report containing peer-connection stats and outbound-track-stats assert_true: Expect statsReport to contain stats object of type outbound-rtp expected true got false
 FAIL getStats() with no argument should return stats for no-stream tracks assert_true: Expect statsReport to contain stats object of type outbound-rtp expected true got false
 FAIL getStats() on track associated with RtpSender should return stats report containing outbound-rtp stats assert_equals: Expect dictionary.remoteId to be string expected "string" but got "undefined"
-FAIL getStats() on track associated with RtpReceiver should return stats report containing inbound-rtp stats promise_test: Unhandled rejection with value: object "InvalidAccessError: Failed to execute 'getStats' on 'RTCPeerConnection': There is no sender or receiver for the track."
+FAIL getStats() on track associated with RtpReceiver should return stats report containing inbound-rtp stats assert_equals: Expect dictionary.codecId to be string expected "string" but got "undefined"
 FAIL getStats() with connected peer connections having tracks and data channel should return all mandatory to implement stats assert_unreached: test failed with error: Error: assert_true: Expect dictionary.dataChannelIdentifier to be integer expected true got false Reached unreachable code
 Harness: the test ran to completion.
 

third_party/blink/web_tests/external/wpt/webrtc/RTCPeerConnection-getStats.https.html

@@ -212,7 +212,8 @@
         pc2.getReceivers()[0].track.addEventListener('unmute', resolve);
       });
     }
-    const stats = await pc2.getStats(track);
+    const receivedTrack = pc2.getReceivers()[0].track;
+    const stats = await pc2.getStats(receivedTrack);
     validateStatsReport(stats);
     assert_stats_report_has_stats(stats, ['inbound-rtp']);
   }, `getStats() on track associated with RtpReceiver should return stats report containing inbound-rtp stats`);

third_party/blink/web_tests/virtual/webrtc-wpt-plan-b/external/wpt/webrtc/RTCPeerConnection-getStats.https-expected.txt

@@ -10,7 +10,7 @@ PASS getStats() with no argument should return stats report containing peer-conn
 FAIL getStats() with no argument should return stats report containing peer-connection stats and outbound-track-stats assert_true: Expect statsReport to contain stats object of type outbound-rtp expected true got false
 FAIL getStats() with no argument should return stats for no-stream tracks assert_true: Expect statsReport to contain stats object of type outbound-rtp expected true got false
 FAIL getStats() on track associated with RtpSender should return stats report containing outbound-rtp stats assert_equals: Expect dictionary.remoteId to be string expected "string" but got "undefined"
-FAIL getStats() on track associated with RtpReceiver should return stats report containing inbound-rtp stats promise_test: Unhandled rejection with value: object "InvalidAccessError: Failed to execute 'getStats' on 'RTCPeerConnection': There is no sender or receiver for the track."
+FAIL getStats() on track associated with RtpReceiver should return stats report containing inbound-rtp stats assert_equals: Expect dictionary.codecId to be string expected "string" but got "undefined"
 FAIL getStats() with connected peer connections having tracks and data channel should return all mandatory to implement stats assert_unreached: test failed with error: Error: assert_true: Expect dictionary.dataChannelIdentifier to be integer expected true got false Reached unreachable code
 Harness: the test ran to completion.