webrtc wpt: add max-bundle test

checking the
  If the remote endpoint is not bundle-aware,
  negotiate only one media track
condition of
  https://w3c.github.io/webrtc-pc/#dom-rtcbundlepolicy-max-bundle
Currently failing

BUG=webrtc:13274

Change-Id: I7e5272753a0b0d2b22c050851d1e5bb517fd04eb
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/3222949
Reviewed-by: Harald Alvestrand <hta@chromium.org>
Commit-Queue: Philipp Hancke <philipp.hancke@googlemail.com>
Cr-Commit-Position: refs/heads/main@{#931977}

webrtc/protocol/bundle.https.html

@@ -91,4 +91,38 @@
   assert_not_equals(dtlsTransports[1], secondTransport);
   assert_equals(secondTransport.state, 'closed');
 }, 'bundles on the first transport and closes the second');
+
+promise_test(async t => {
+  const sdp = `v=0
+o=- 0 3 IN IP4 127.0.0.1
+s=-
+t=0 0
+a=fingerprint:sha-256 A7:24:72:CA:6E:02:55:39:BA:66:DF:6E:CC:4C:D8:B0:1A:BF:1A:56:65:7D:F4:03:AD:7E:77:43:2A:29:EC:93
+a=ice-ufrag:ETEn
+a=ice-pwd:OtSK0WpNtpUjkY4+86js7Z/l
+m=audio 9 UDP/TLS/RTP/SAVPF 111
+c=IN IP4 0.0.0.0
+a=rtcp-mux
+a=sendonly
+a=mid:audio
+a=rtpmap:111 opus/48000/2
+a=setup:actpass
+m=video 9 UDP/TLS/RTP/SAVPF 100
+c=IN IP4 0.0.0.0
+a=rtcp-mux
+a=sendonly
+a=mid:video
+a=rtpmap:100 VP8/90000
+a=fmtp:100 max-fr=30;max-fs=3600
+a=setup:actpass
+`;
+  const pc = new RTCPeerConnection({ bundlePolicy: 'max-bundle' });
+  t.add_cleanup(() => pc.close());
+  await pc.setRemoteDescription({ type: 'offer', sdp });
+  await pc.setLocalDescription();
+  const transceivers = pc.getTransceivers();
+  assert_equals(transceivers.length, 2);
+  assert_false(transceivers[0].stopped);
+  assert_true(transceivers[1].stopped);
+}, 'max-bundle with an offer without bundle only negotiates the first m-line');
 </script>