Add test for setCodecPreferences with shortened codec list

Bug: none
Change-Id: Ibf43c6968f8fc3b38668fb636eeeb5094916453d
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2039671Reviewed-by: Marina Ciocea <marinaciocea@chromium.org>
Commit-Queue: Harald Alvestrand <hta@chromium.org>
Cr-Commit-Position: refs/heads/master@{#738896}

third_party/blink/web_tests/external/wpt/webrtc/RTCRtpTransceiver-setCodecPreferences.html

@@ -77,6 +77,23 @@
 
   }, `setCodecPreferences() with reordered codecs should succeed`);
 
+  test(() => {
+    const pc = new RTCPeerConnection();
+    const transceiver = pc.addTransceiver('video');
+    const capabilities = RTCRtpSender.getCapabilities('video');
+    const { codecs } = capabilities;
+    // This test verifies that the mandatory VP8 codec is present
+    // and can be set.
+    let tried = false;
+    codecs.forEach(codec => {
+      if (codec.mimeType.toLowerCase() === 'video/vp8') {
+        transceiver.setCodecPreferences([codecs[0]]);
+        tried = true;
+      }
+    });
+    assert_true(tried, 'VP8 video codec was found and tried');
+  }, `setCodecPreferences() with only one video codec should succeed`);
+
   test(() => {
     const pc = new RTCPeerConnection();
     const transceiver = pc.addTransceiver('audio');

third_party/blink/web_tests/virtual/webrtc-wpt-plan-b/external/wpt/webrtc/RTCRtpTransceiver-setCodecPreferences-expected.txt

@@ -4,6 +4,7 @@ FAIL setCodecPreferences() on video transceiver with codecs returned from RTCRtp
 FAIL setCodecPreferences() with both sender receiver codecs combined should succeed Failed to execute 'addTransceiver' on 'RTCPeerConnection': This operation is only supported in 'unified-plan'.
 FAIL setCodecPreferences([]) should succeed Failed to execute 'addTransceiver' on 'RTCPeerConnection': This operation is only supported in 'unified-plan'.
 FAIL setCodecPreferences() with reordered codecs should succeed Failed to execute 'addTransceiver' on 'RTCPeerConnection': This operation is only supported in 'unified-plan'.
+FAIL setCodecPreferences() with only one video codec should succeed Failed to execute 'addTransceiver' on 'RTCPeerConnection': This operation is only supported in 'unified-plan'.
 FAIL setCodecPreferences() on audio transceiver with codecs returned from getCapabilities('video') should throw InvalidModificationError Failed to execute 'addTransceiver' on 'RTCPeerConnection': This operation is only supported in 'unified-plan'.
 FAIL setCodecPreferences() with user defined codec with invalid mimeType should throw InvalidModificationError Failed to execute 'addTransceiver' on 'RTCPeerConnection': This operation is only supported in 'unified-plan'.
 FAIL setCodecPreferences() with user defined codec should throw InvalidModificationError Failed to execute 'addTransceiver' on 'RTCPeerConnection': This operation is only supported in 'unified-plan'.